Malenaadu: February 2011

DataStructure Program to convert an Infix expression to Prefix form.

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <ctype.h>
#define MAX 50
struct infix
{
char target[MAX] ;
char stack[MAX] ;
char *s, *t ;
int top, l ;
} ;
void initinfix ( struct infix * ) ;
void setexpr ( struct infix *, char * ) ;
void push ( struct infix *, char ) ;
char pop ( struct infix * ) ;
void convert ( struct infix * ) ;
int priority ( char c ) ;
void show ( struct infix ) ;
void main( )
{
struct infix q ;
char expr[MAX] ;
clrscr( ) ;
initinfix ( &q ) ;
printf ( "\nEnter an expression in infix form: " ) ;
gets ( expr ) ;
setexpr ( &q, expr ) ;
convert ( &q ) ;
printf ( "The Prefix expression is: " ) ;
show ( q ) ;
getch( ) ;
}
/* initializes elements of structure variable */
void initinfix ( struct infix *pq )
{
pq -> top = -1 ;
strcpy ( pq -> target, "" ) ;
strcpy ( pq -> stack, "" ) ;
pq -> l = 0 ;
}
/* reverses the given expression */
void setexpr ( struct infix *pq, char *str )
{
pq -> s = str ;
strrev ( pq -> s ) ;
pq -> l = strlen ( pq -> s ) ;
*( pq -> target + pq -> l ) = '\0' ;
pq -> t = pq -> target + ( pq -> l - 1 ) ;
}
/* adds operator to the stack */
void push ( struct infix *pq, char c )
{
if ( pq -> top == MAX - 1 )
printf ( "\nStack is full.\n" ) ;
else
{
pq -> top++ ;
pq -> stack[pq -> top] = c ;
}
}
/* pops an operator from the stack */
char pop ( struct infix *pq )
{
if ( pq -> top == -1 )
{
printf ( "Stack is empty\n" ) ;
return -1 ;
}
else
{
char item = pq -> stack[pq -> top] ;
pq -> top-- ;
return item ;
}
}
/* converts the infix expr. to prefix form */
void convert ( struct infix *pq )
{
char opr ;
while ( *( pq -> s ) )
{
if ( *( pq -> s ) == ' ' || *( pq -> s ) == '\t' )
{
pq -> s++ ;
continue ;
}
if ( isdigit ( *( pq -> s ) ) || isalpha ( *( pq -> s ) ) )
{
while ( isdigit ( *( pq -> s ) ) || isalpha ( *( pq -> s ) ) )
{
*( pq -> t ) = *( pq -> s ) ;
pq -> s++ ;
pq -> t-- ;
}
}
if ( *( pq -> s ) == ')' )
{
push ( pq, *( pq -> s ) ) ;
pq -> s++ ;
}
if ( *( pq -> s ) == '*' || *( pq -> s ) == '+' || *( pq -> s ) == '/' || *( pq -> s ) == '%' || *( pq -> s ) == '-' || *( pq -> s ) == '$' )
{
if ( pq -> top != -1 )
{
opr = pop ( pq ) ;
while ( priority ( opr ) > priority ( *( pq -> s ) ) )
{
*( pq -> t ) = opr ;
pq -> t-- ;
opr = pop ( pq ) ;
}
push ( pq, opr ) ;
push ( pq, *( pq -> s ) ) ;
}
else
push ( pq, *( pq -> s ) ) ;
pq -> s++ ;
}
if ( *( pq -> s ) == '(' )
{
opr = pop ( pq ) ;
while ( opr != ')' )
{
*( pq -> t ) = opr ;
pq -> t-- ;
opr = pop ( pq ) ;
}
pq -> s++ ;
}
}
while ( pq -> top != -1 )
{
opr = pop ( pq ) ;
*( pq -> t ) = opr ;
pq -> t-- ;
}
pq -> t++ ;
}
/* returns the priotity of the operator */
int priority ( char c )
{
if ( c == '$' )
return 3 ;
if ( c == '*' || c == '/' || c == '%' )
return 2 ;
else
{
if ( c == '+' || c == '-' )
return 1 ;
else
return 0 ;
}
}
/* displays the prefix form of given expr. */
void show ( struct infix pq )
{
while ( *( pq.t ) )
{
printf ( " %c", *( pq.t ) ) ;
pq.t++ ;
}
}

DataStructure Program to merge two 1-D arrays

#include <stdio.h>
#include <conio.h>

#include <alloc.h>
#define MAX1 5
#define MAX2 7
int *arr ;
int* create ( int ) ;
void sort ( int *, int ) ;
void display ( int *, int ) ;
int* merge ( int *, int * ) ;
void main( )
{
int *a, *b, *c ;
clrscr( ) ;
printf ( "\nEnter elements for first array: \n\n" ) ;
a = create ( MAX1 ) ;
printf ( "\nEnter elements for second array: \n\n" ) ;
b = create ( MAX2 ) ;
sort ( a, MAX1 ) ;
sort ( b, MAX2 ) ;
printf ( "\nFirst array: \n" ) ;
display ( a, MAX1 ) ;
printf ( "\n\nSecond array: \n" ) ;
display ( b, MAX2 ) ;
printf ( "\n\nAfter Merging: \n" ) ;
c = merge ( a, b ) ;
display ( c, MAX1 + MAX2 ) ;
getch( ) ;
}
/* creates array of given size, dynamically */
int* create ( int size )
{
int *arr, i ;
arr = ( int * ) malloc ( sizeof ( int ) * size ) ;
for ( i = 0 ; i < size ; i++ )
{
printf ( "Enter the element no. %d: ", i + 1 ) ;
scanf ( "%d", &arr[i] ) ;
}
return arr ;
}
/* sorts array in ascending order */
void sort ( int *arr, int size )
{
int i, temp, j ;
for ( i = 0 ; i < size ; i++ )
{
for ( j = i + 1 ; j < size ; j++ )
{
if ( arr[i] > arr[j] )
{
temp = arr[i] ;
arr[i] = arr[j] ;
arr[j] = temp ;
}
}
}
}
/* displays the contents of array */
void display ( int *arr, int size )
{
int i ;
for ( i = 0 ; i < size ; i++)
printf ( "%d\t", arr[i] ) ;
}
/* merges two arrays of different size */
int* merge ( int *a, int *b )
{
int *arr ;
int i, k, j ;
int size = MAX1 + MAX2 ;
arr = ( int * ) malloc ( sizeof ( int ) * ( size ) ) ;
for ( k = 0, j = 0, i = 0 ; i <= size ; i++ )
{
if ( a[k] < b[j] )
{
arr[i] = a[k] ;
k++ ;
if ( k >= MAX1 )
{
for ( i++ ; j < MAX2 ; j++, i++ )
arr[i] = b[j] ;
}
}
else
{
arr[i] = b[j] ;
j++ ;
if ( j >= MAX2 )
{
for ( i++ ; k < MAX1 ; k++, i++ )
arr[i] = a[k] ;
}
}
}
return arr ;
}

DataStructure-Program to merge two linked list

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure containing a data part and link part */
struct node
{
int data ;
struct node *link ;
} ;
void add ( struct node **, int ) ;
void display ( struct node * ) ;
int count ( struct node * ) ;
void merge ( struct node *, struct node *, struct node ** ) ;
void main( )
{
struct node *first, *second, *third ;
first = second = third = NULL ; /* empty linked lists */
add ( &first, 9 ) ;
add ( &first, 12 ) ;
add ( &first, 14 ) ;
add ( &first, 17 ) ;
add ( &first, 35 ) ;
add ( &first, 61 ) ;
add ( &first, 79 ) ;
clrscr( ) ;
printf ( "First linked list : " ) ;
display ( first ) ;
printf ( "\nNo. of elements in Linked List : %d" , count ( first ) ) ;
add ( &second, 12 ) ;
add ( &second, 17 ) ;
add ( &second, 24 ) ;
add ( &second, 36 ) ;
add ( &second, 59 ) ;
add ( &second, 64 ) ;
add ( &second, 87 ) ;
printf ( "\n\nSecond linked list : " ) ;
display ( second ) ;
printf ( "\nNo. of elements in Linked List : %d" , count ( second ) ) ;
merge ( first, second, &third ) ;
printf ( "\n\nThe merged list : " ) ;
display ( third ) ;
printf ( "\nNo. of elements in Linked List : %d", count ( third ) ) ;
}
/* adds node to an ascending order linked list */
void add ( struct node **q, int num )
{
struct node *r, *temp = *q ;
r = malloc ( sizeof ( struct node ) ) ;
r -> data = num ;
/* if list is empty or if new node is to be inserted before the first node */
if ( *q == NULL || ( *q ) -> data > num )
{
*q = r ;
( *q ) -> link = temp ;
}
else
{
/* traverse the entire linked list to search the position to insert the new node */
while ( temp != NULL )
{
if ( temp -> data < num && ( temp -> link -> data > num || temp -> link == NULL ))
{
r -> link = temp -> link ;
temp -> link = r ;
return ;
}
temp = temp -> link ; /*go to next node */
}
r -> link = NULL ;
temp -> link = r ;
}
}
/* displays the contents of the linked list */
void display ( struct node *q )
{
printf ( "\n" ) ;
/* traverse the entire linked list */
while ( q != NULL )
{
printf ( "%d ", q -> data ) ;
q = q -> link ;
}
}
/* counts the number of nodes present in the linked list */
int count ( struct node * q )
{
int c = 0 ;
/* traverse the entire linked list */
while ( q != NULL )
{
q = q -> link ;
c++ ;
}
return c ;
}
/* merges the two linked lists, restricting the common elements to occur only once in the final list */
void merge ( struct node *p, struct node *q, struct node **s )
{
struct node *z ;
z = NULL ;
/* if both lists are empty */
if ( p == NULL && q == NULL )
return ;
/* traverse both linked lists till the end. If end of any one list is reached loop is terminated */
while ( p != NULL && q != NULL )
{
/* if node being added in the first node */
if ( *s == NULL )
{ *s = malloc ( sizeof ( struct node ) ) ;
z = *s ;
}
else
{
z -> link = malloc ( sizeof ( struct node ) ) ;
z = z -> link ;
}
if ( p -> data < q -> data )
{
z -> data = p -> data ;
p = p -> link ;
}
else
{
if ( q -> data < p -> data )
{
z -> data = q -> data ;
q = q -> link ;
}
else
{
if ( p -> data == q -> data )
{
z -> data = q -> data ;
p = p -> link ;
q = q -> link ;
}
}
}
}
/* if end of first list has not been reached */
while ( p != NULL )
{
z -> link = malloc ( sizeof ( struct node ) ) ;
z = z -> link ;
z -> data = p -> data ;
p = p -> link ;
}
/* if end of second list has been reached */
while ( q != NULL )
{
z -> link = malloc ( sizeof ( struct node ) ) ;
z = z -> link ;
z -> data = q -> data ;
q = q -> link ;
}
z -> link = NULL ;
}

DataStructure Program to maintain an AVL tree

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
#define FALSE 0
#define TRUE 1
struct AVLNode
{
int data ;
int balfact ;
struct AVLNode *left ;
struct AVLNode *right ;
} ;
struct AVLNode * buildtree ( struct AVLNode *, int, int * ) ;
struct AVLNode * deldata ( struct AVLNode *, int, int * ) ;
struct AVLNode * del ( struct AVLNode *, struct AVLNode *, int * ) ;
struct AVLNode * balright ( struct AVLNode *, int * ) ;
struct AVLNode * balleft ( struct AVLNode *, int * ) ;
void display ( struct AVLNode * ) ;
void deltree ( struct AVLNode * ) ;
void main( )
{
struct AVLNode *avl = NULL ;
int h ;
clrscr( ) ;
avl = buildtree ( avl, 20, &h ) ;
avl = buildtree ( avl, 6, &h ) ;
avl = buildtree ( avl, 29, &h ) ;
avl = buildtree ( avl, 5, &h ) ;
avl = buildtree ( avl, 12, &h ) ;
avl = buildtree ( avl, 25, &h ) ;
avl = buildtree ( avl, 32, &h ) ;
avl = buildtree ( avl, 10, &h ) ;
avl = buildtree ( avl, 15, &h ) ;
avl = buildtree ( avl, 27, &h ) ;
avl = buildtree ( avl, 13, &h ) ;
printf ( "\nAVL tree:\n" ) ;
display ( avl ) ;
avl = deldata ( avl, 20, &h ) ;
avl = deldata ( avl, 12, &h ) ;
printf ( "\nAVL tree after deletion of a node:\n" ) ;
display ( avl ) ;
deltree ( avl ) ;
getch( ) ;
}
/* inserts an element into tree */
struct AVLNode * buildtree ( struct AVLNode *root, int data, int *h )
{
struct AVLNode *node1, *node2 ;
if ( !root )
{
root = ( struct AVLNode * ) malloc ( sizeof ( struct AVLNode ) ) ;
root -> data = data ;
root -> left = NULL ;
root -> right = NULL ;
root -> balfact = 0 ;
*h = TRUE ;
return ( root ) ;
}
if ( data < root -> data )
{
root -> left = buildtree ( root -> left, data, h ) ;
/* If left subtree is higher */
if ( *h )
{
switch ( root -> balfact )
{
case 1:
node1 = root -> left ;
if ( node1 -> balfact == 1 )
{
printf ( "\nRight rotation along %d.", root -> data ) ;
root -> left = node1 -> right ;
node1 -> right = root ;
root -> balfact = 0 ;
root = node1 ;
}
else
{
printf ( "\nDouble rotation, left along %d", node1 -> data ) ;
node2 = node1 -> right ;
node1 -> right = node2 -> left ;
printf ( " then right along %d.\n", root -> data ) ;
node2 -> left = node1 ;
root -> left = node2 -> right ;
node2 -> right = root ;
if ( node2 -> balfact == 1 )
root -> balfact = -1 ;
else
root -> balfact = 0 ;
if ( node2 -> balfact == -1 )
node1 -> balfact = 1 ;
else
node1 -> balfact = 0 ;
root = node2 ;
}
root -> balfact = 0 ;
*h = FALSE ;
break ;
case 0:
root -> balfact = 1 ;
break ;
case -1:
root -> balfact = 0 ;
*h = FALSE ;
}
}
}
if ( data > root -> data )
{
root -> right = buildtree ( root -> right, data, h ) ;
/* If the right subtree is higher */
if ( *h )
{
switch ( root -> balfact )
{
case 1:
root -> balfact = 0 ;
*h = FALSE ;
break ;
case 0:
root -> balfact = -1 ;
break;
case -1:
node1 = root -> right ;
if ( node1 -> balfact == -1 )
{
printf ( "\nLeft rotation along %d.", root -> data ) ;
root -> right = node1 -> left ;
node1 -> left = root ;
root -> balfact = 0 ;
root = node1 ;
}
else
{
printf ( "\nDouble rotation, right along %d", node1 -> data ) ;
node2 = node1 -> left ;
node1 -> left = node2 -> right ;
node2 -> right = node1 ;
printf ( " then left along %d.\n", root -> data ) ;
root -> right = node2 -> left ;
node2 -> left = root ;
if ( node2 -> balfact == -1 )
root -> balfact = 1 ;
else
root -> balfact = 0 ;
if ( node2 -> balfact == 1 )
node1 -> balfact = -1 ;
else
node1 -> balfact = 0 ;
root = node2 ;
}
root -> balfact = 0 ;
*h = FALSE ;
}
}
}
return ( root ) ;
}
/* deletes an item from the tree */
struct AVLNode * deldata ( struct AVLNode *root, int data, int *h )
{
struct AVLNode *node ;
if ( !root )
{
printf ( "\nNo such data." ) ;
return ( root ) ;
}
else
{
if ( data < root -> data )
{
root -> left = deldata ( root -> left, data, h ) ;
if ( *h )
root = balright ( root, h ) ;
}
else
{
if ( data > root -> data )
{
root -> right = deldata ( root -> right, data, h ) ;
if ( *h )
root = balleft ( root, h ) ;
}
else
{
node = root ;
if ( node -> right == NULL )
{
root = node -> left ;
*h = TRUE ;
free ( node ) ;
}
else
{
if ( node -> left == NULL )
{
root = node -> right ;
*h = TRUE ;
free ( node ) ;
}
else
{
node -> right = del ( node -> right, node, h ) ;
if ( *h )
root = balleft ( root, h ) ;
}
}
}
}
}
return ( root ) ;
}
struct AVLNode * del ( struct AVLNode *succ, struct AVLNode *node, int *h )
{
struct AVLNode *temp = succ ;
if ( succ -> left != NULL )
{
succ -> left = del ( succ -> left, node, h ) ;
if ( *h )
succ = balright ( succ, h ) ;
}
else
{
temp = succ ;
node -> data = succ -> data ;
succ = succ -> right ;
free ( temp ) ;
*h = TRUE ;
}
return ( succ ) ;
}
/* balances the tree, if right sub-tree is higher */
struct AVLNode * balright ( struct AVLNode *root, int *h )
{
struct AVLNode *node1, *node2 ;
switch ( root -> balfact )
{
case 1:
root -> balfact = 0 ;
break;
case 0:
root -> balfact = -1 ;
*h = FALSE ;
break;
case -1:
node1 = root -> right ;
if ( node1 -> balfact <= 0 )
{
printf ( "\nLeft rotation along %d.", root -> data ) ;
root -> right = node1 -> left ;
node1 -> left = root ;
if ( node1 -> balfact == 0 )
{
root -> balfact = -1 ;
node1 -> balfact = 1 ;
*h = FALSE ;
}
else
{
root -> balfact = node1 -> balfact = 0 ;
}
root = node1 ;
}
else
{
printf ( "\nDouble rotation, right along %d", node1 -> data );
node2 = node1 -> left ;
node1 -> left = node2 -> right ;
node2 -> right = node1 ;
printf ( " then left along %d.\n", root -> data );
root -> right = node2 -> left ;
node2 -> left = root ;
if ( node2 -> balfact == -1 )
root -> balfact = 1 ;
else
root -> balfact = 0 ;
if ( node2 -> balfact == 1 )
node1 -> balfact = -1 ;
else
node1 -> balfact = 0 ;
root = node2 ;
node2 -> balfact = 0 ;
}
}
return ( root ) ;
}
/* balances the tree, if left sub-tree is higher */
struct AVLNode * balleft ( struct AVLNode *root, int *h )
{
struct AVLNode *node1, *node2 ;
switch ( root -> balfact )
{
case -1:
root -> balfact = 0 ;
break ;
case 0:
root -> balfact = 1 ;
*h = FALSE ;
break ;
case 1:
node1 = root -> left ;
if ( node1 -> balfact >= 0 )
{ printf ( "\nRight rotation along %d.", root -> data ) ;
root -> left = node1 -> right ;
node1 -> right = root ;
if ( node1 -> balfact == 0 )
{
root -> balfact = 1 ;
node1 -> balfact = -1 ;
*h = FALSE ;
}
else
{
root -> balfact = node1 -> balfact = 0 ;
}
root = node1 ;
}
else
{
printf ( "\nDouble rotation, left along %d", node1 -> data ) ;
node2 = node1 -> right ;
node1 -> right = node2 -> left ;
node2 -> left = node1 ;
printf ( " then right along %d.\n", root -> data ) ;
root -> left = node2 -> right ;
node2 -> right = root ;
if ( node2 -> balfact == 1 )
root -> balfact = -1 ;
else
root -> balfact = 0 ;
if ( node2-> balfact == -1 )
node1 -> balfact = 1 ;
else
node1 -> balfact = 0 ;
root = node2 ;
node2 -> balfact = 0 ;
}
}
return ( root ) ;
}
/* displays the tree in-order */
void display ( struct AVLNode *root )
{
if ( root != NULL )
{
display ( root -> left ) ;
printf ( "%d\t", root -> data ) ;
display ( root -> right ) ;
}
}
/* deletes the tree */
void deltree ( struct AVLNode *root )
{
if ( root != NULL )
{
deltree ( root -> left ) ;
deltree ( root -> right ) ;
}
free ( root ) ;
}

DataStructure Program to maintain a threaded binary tree

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
enum boolean
{
false = 0,
true = 1
} ;
struct thtree
{
enum boolean isleft ;
struct thtree *left ;
int data ;
struct thtree *right ;
enum boolen isright ;
} ;
void insert ( struct thtree **, int ) ;
void delete ( struct thtree **, int ) ;
void search ( struct thtree **, int, struct thtree **,struct thtree **, int * ) ;
void inorder ( struct thtree * ) ;
void deltree ( struct thtree ** ) ;
void main( )
{
struct thtree *th_head ;
th_head = NULL ; /* empty tree */
insert ( &th_head, 11 ) ;
insert ( &th_head, 9 ) ;
insert ( &th_head, 13 ) ;
insert ( &th_head, 8 ) ;
insert ( &th_head, 10 ) ;
insert ( &th_head, 12 ) ;
insert ( &th_head, 14 ) ;
insert ( &th_head, 15 ) ;
insert ( &th_head, 7 ) ;
clrscr( ) ;
printf ( "Threaded binary tree before deletion:\n" ) ;
inorder ( th_head ) ;
delete ( &th_head, 10 ) ;
printf ( "\nThreaded binary tree after deletion:\n" ) ;
inorder ( th_head ) ;
delete ( &th_head, 14 ) ;
printf ( "\nThreaded binary tree after deletion:\n" ) ;
inorder ( th_head ) ;
delete ( &th_head, 8 ) ;
printf ( "\nThreaded binary tree after deletion:\n" ) ;
inorder ( th_head ) ;
delete ( &th_head, 13 ) ;
printf ( "\nThreaded binary tree after deletion:\n" ) ;
inorder ( th_head ) ;
deltree ( &th_head ) ;
getch( ) ;
}
/* inserts a node in a threaded binary tree */
void insert ( struct thtree **s, int num )
{
struct thtree *p, *z, *head = *s ;
/* allocating a new node */
z = malloc ( sizeof ( struct thtree ) ) ;
z -> isleft = true ; /* indicates a thread */
z -> data = num ; /* assign new data */
z -> isright = true ; /* indicates a thread */
/* if tree is empty */
if ( *s == NULL )
{
head = malloc ( sizeof ( struct thtree ) ) ;
/* the entire tree is treated as a left sub-tree of the head node */
head -> isleft = false ;
head -> left = z ; /* z becomes leftchild of the head node */
head -> data = -9999 ; /* no data */
head -> right = head ; /* right link will always be pointing to itself */
head -> isright = false ;
*s = head ;
z -> left = head ; /* left thread to head */
z -> right = head ; /* right thread to head */
}
else /* if tree is non-empty */
{
p = head -> left ;
/* traverse till the thread is found attached to the head */
while ( p != head )
{
if ( p -> data > num )
{
if ( p -> isleft != true ) /* checking for a thread */
p = p -> left ;
else
{
z -> left = p -> left ;
p -> left = z ;
p -> isleft = false ; /* indicates a link */
z -> isright = true ;
z -> right = p ;
return ;
}
}
else
{
if ( p -> data < num )
{
if ( p -> isright != true )
p = p -> right ;
else
{
z -> right = p -> right ;
p -> right = z ;
p -> isright = false ; /* indicates a link */
z -> isleft = true ;
z -> left = p ;
return ;
}
}
}
}
}
}
/* deletes a node from the binary search tree */
void delete ( struct thtree **root, int num )
{
int found ;
struct thtree *parent, *x, *xsucc ;
/* if tree is empty */
if ( *root == NULL )
{
printf ( "\nTree is empty" ) ;
return ;
}
parent = x = NULL ;
/* call to search function to find the node to be deleted */
search ( root, num, &parent, &x, &found ) ;
/* if the node to deleted is not found */
if ( found == false )
{
printf ( "\nData to be deleted, not found" ) ;
return ;
}
/* if the node to be deleted has two children */
if ( x -> isleft == false && x -> isright == false )
{
parent = x ;
xsucc = x -> right ;
while ( xsucc -> isleft == false )
{
parent = xsucc ;
xsucc = xsucc -> left ;
}
x -> data = xsucc -> data ;
x = xsucc ;
}
/* if the node to be deleted has no child */
if ( x -> isleft == true && x -> isright == true )
{
/* if node to be deleted is a root node */
if ( parent == NULL )
{
( *root ) -> left = *root ;
( *root ) -> isleft = true ;
free ( x ) ;
return ;
}
if ( parent -> right == x )
{
parent -> isright = true ;
parent -> right = x -> right ;
}
else
{
parent -> isleft = true ;
parent -> left = x -> left ;
}
free ( x ) ;
return ;
}
/* if the node to be deleted has only rightchild */
if ( x -> isleft == true && x -> isright == false )
{
/* node to be deleted is a root node */
if ( parent == NULL )
{
( *root ) -> left = x -> right ;
free ( x ) ;
return ;
}
if ( parent -> left == x )
{
parent -> left = x -> right ;
x -> right -> left = x -> left ;
}
else
{
parent -> right = x -> right ;
x -> right -> left = parent ;
}
free ( x ) ;
return ;
}
/* if the node to be deleted has only left child */
if ( x -> isleft == false && x -> isright == true )
{
/* the node to be deleted is a root node */
if ( parent == NULL )
{
parent = x ;
xsucc = x -> left ;
while ( xsucc -> right == false )
xsucc = xsucc -> right ;
xsucc -> right = *root ;
( *root ) -> left = x -> left ;
free ( x ) ;
return ;
}
if ( parent -> left == x )
{
parent -> left = x -> left ;
x -> left -> right = parent ;
}
else
{
parent -> right = x -> left ;
x -> left -> right = x -> right ;
}
free ( x ) ;
return ;
}
}
/* returns the address of the node to be deleted, address of its parent and whether the node is found or not */
void search ( struct thtree **root, int num, struct thtree **par, struct thtree **x, int *found )
{
struct thtree *q ;
q = ( *root ) -> left ;
*found = false ;
*par = NULL ;
while ( q != *root )
{
/* if the node to be deleted is found */
if ( q -> data == num )
{
*found = true ;
*x = q ;
return ;
}
*par = q ;
if ( q -> data > num )
{
if ( q -> isleft == true )
{
*found = false ;
x = NULL ;
return ;
}
q = q -> left ;
}
else
{
if ( q -> isright == true )
{
*found = false ;
*x = NULL ;
return ;
}
q = q -> right ;
}
}
}
/* traverses the threaded binary tree in inorder */
void inorder ( struct thtree *root )
{
struct thtree *p ;
p = root -> left ;
while ( p != root )
{
while ( p -> isleft == false )
p = p -> left ;
printf ( "%d\t", p -> data ) ;
while ( p -> isright == true )
{
p = p -> right ;
if ( p == root )
break ;
printf ( "%d\t", p -> data ) ;
}
p = p -> right ;
}
}
void deltree ( struct thtree **root )
{
while ( ( *root ) -> left != *root )
delete ( root, ( *root ) -> left -> data ) ;
}

DataStructure Program to implement a circular queue as a linked list

DataStructure-Program to implement a circular queue as a linked list.

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure containing a data part and link part */
struct node
{
int data ;
struct node * link ;
} ;
void addcirq ( struct node **, struct node **, int ) ;
int delcirq ( struct node **, struct node ** ) ;
void cirq_display ( struct node * ) ;
void main( )
{
struct node *front, *rear ;
front = rear = NULL ;
addcirq ( &front, &rear, 10 ) ;
addcirq ( &front, &rear, 17 ) ;
addcirq ( &front, &rear, 18 ) ;
addcirq ( &front, &rear, 5 ) ;
addcirq ( &front, &rear, 30 ) ;
addcirq ( &front, &rear, 15 ) ;
clrscr( ) ;
printf ( "Before deletion:\n" ) ;
cirq_display ( front ) ;
delcirq ( &front, &rear ) ;
delcirq ( &front, &rear ) ;
delcirq ( &front, &rear ) ;
printf ( "\n\nAfter deletion:\n" ) ;
cirq_display ( front ) ;
}
/* adds a new element at the end of queue */
void addcirq ( struct node **f, struct node **r, int item )
{
struct node *q ;
/* create new node */
q = malloc ( sizeof ( struct node ) ) ;
q -> data = item ;
/* if the queue is empty */
if ( *f == NULL )
*f = q ;
else
( *r ) -> link = q ;
*r = q ;
( *r ) -> link = *f ;
}
/* removes an element from front of queue */
int delcirq ( struct node **f, struct node **r )
{
struct node *q ;
int item ;
/* if queue is empty */
if ( *f == NULL )
printf ( "queue is empty" ) ;
else
{
if ( *f == *r )
{
item = ( *f ) -> data ;
free ( *f ) ;
*f = NULL ;
*r = NULL ;
}
else
{
/* delete the node */
q = *f ;
item = q -> data ;
*f = ( *f ) -> link ;
( *r ) -> link = *f ;
free ( q ) ;
}
return ( item ) ;
}
return NULL ;
}
/* displays whole of the queue */
void cirq_display ( struct node *f )
{
struct node *q = f, *p = NULL ;
/* traverse the entire linked list */
while ( q != p )
{
printf ( "%d\t", q -> data ) ;
q = q -> link ;
p = f ;
}
}

DataStructure Program to maintain a double linked list

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure representing a node of the doubly linked list */
struct dnode
{
struct dnode *prev ;
int data ;
struct dnode * next ;
} ;
void d_append ( struct dnode **, int ) ;
void d_addatbeg ( struct dnode **, int ) ;
void d_addafter ( struct dnode *, int , int ) ;
void d_display ( struct dnode * ) ;
int d_count ( struct dnode * ) ;
void d_delete ( struct dnode **, int ) ;
void main( )
{
struct dnode *p ;
p = NULL ; /* empty doubly linked list */
d_append ( &p , 11 ) ;
d_append ( &p , 2 ) ;
d_append ( &p , 14 ) ;
d_append ( &p , 17 ) ;
d_append ( &p , 99 ) ;
clrscr( ) ;
d_display ( p ) ;
printf ( "\nNo. of elements in the DLL = %d\n", d_count ( p ) ) ;
d_addatbeg ( &p, 33 ) ;
d_addatbeg ( &p, 55 ) ;
d_display ( p ) ;
printf ( "\nNo. of elements in the DLL = %d\n", d_count ( p ) ) ;
d_addafter ( p, 4, 66 ) ;
d_addafter ( p, 2, 96 ) ;
d_display ( p ) ;
printf ( "\nNo. of elements in the DLL = %d\n", d_count ( p ) ) ;
d_delete ( &p, 55 ) ;
d_delete ( &p, 2 ) ;
d_delete ( &p, 99 ) ;
d_display ( p ) ;
printf ( "\nNo. of elements in the DLL = %d\n", d_count ( p ) ) ;
}
/* adds a new node at the end of the doubly linked list */
void d_append ( struct dnode **s, int num )
{
struct dnode *r, *q = *s ;
/* if the linked list is empty */
if ( *s == NULL )
{
/*create a new node */
*s = malloc ( sizeof ( struct dnode ) ) ;
( *s ) -> prev = NULL ;
( *s ) -> data = num ;
( *s ) -> next = NULL ;
}
else
{
/* traverse the linked list till the last node is reached */
while ( q -> next != NULL )
q = q -> next ;
/* add a new node at the end */
r = malloc ( sizeof ( struct dnode ) ) ;
r -> data = num ;
r -> next = NULL ;
r -> prev = q ;
q -> next = r ;
}
}
/* adds a new node at the begining of the linked list */
void d_addatbeg ( struct dnode **s, int num )
{
struct dnode *q ;
/* create a new node */
q = malloc ( sizeof ( struct dnode ) ) ;
/* assign data and pointer to the new node */
q -> prev = NULL ;
q -> data = num ;
q -> next = *s ;
/* make new node the head node */
( *s ) -> prev = q ;
*s = q ;
}
/* adds a new node after the specified number of nodes */
void d_addafter ( struct dnode *q, int loc, int num )
{
struct dnode *temp ;
int i ;
/* skip to desired portion */
for ( i = 0 ; i < loc ; i++ )
{
q = q -> next ;
/* if end of linked list is encountered */
if ( q == NULL )
{ printf ( "\nThere are less than %d elements", loc );
return ;
}
}
/* insert new node */
q = q -> prev ;
temp = malloc ( sizeof ( struct dnode ) ) ;
temp -> data = num ;
temp -> prev = q ;
temp -> next = q -> next ;
temp -> next -> prev = temp ;
q -> next = temp ;
}
/* displays the contents of the linked list */
void d_display ( struct dnode *q )
{
printf ( "\n" ) ;
/* traverse the entire linked list */
while ( q != NULL )
{
printf ( "%2d\t", q -> data ) ;
q = q -> next ;
}
}
/* counts the number of nodes present in the linked list */
int d_count ( struct dnode * q )
{
int c = 0 ;
/* traverse the entire linked list */
while ( q != NULL )
{
q = q -> next ;
c++ ;
}
return c ;
}
/* deletes the specified node from the doubly linked list */
void d_delete ( struct dnode **s, int num )
{
struct dnode *q = *s ;
/* traverse the entire linked list */
while ( q != NULL )
{
/* if node to be deleted is found */
if ( q -> data == num )
{
/* if node to be deleted is the first node */
if ( q == *s )
{
*s = ( *s ) -> next ;
( *s ) -> prev = NULL ;
}
else
{
/* if node to be deleted is the last node */
if ( q -> next == NULL )
q -> prev -> next = NULL ;
else
/* if node to be deleted is any intermediate node */
{
q -> prev -> next = q -> next ;
q -> next -> prev = q -> prev ;
}
free ( q ) ;
}
return ; /* return back after deletion */
}
q = q -> next ; /* go to next node */
}
printf ( "\n%d not found.", num ) ;
}

DataStructure Program to maintain a linked list

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure containing a data part and link part */
struct node
{
int data ;
struct node * link ;
} ;
void append ( struct node **, int ) ;
void addatbeg ( struct node **, int ) ;
void addafter ( struct node *, int, int ) ;
void display ( struct node * ) ;
int count ( struct node * ) ;
void delete ( struct node **, int ) ;
void main( )
{
struct node *p ;
p = NULL ; /* empty linked list */
printf ( "\nNo. of elements in the Linked List = %d", count ( p ) ) ;
append ( &p, 14 ) ;
append ( &p, 30 ) ;
append ( &p, 25 ) ;
append ( &p, 42 ) ;
append ( &p, 17 ) ;
display ( p ) ;
addatbeg ( &p, 999 ) ;
addatbeg ( &p, 888 ) ;
addatbeg ( &p, 777 ) ;
display ( p ) ;
addafter ( p, 7, 0 ) ;
addafter ( p, 2, 1 ) ;
addafter ( p, 5, 99 ) ;
display ( p ) ;
printf ( "\nNo. of elements in the Linked List = %d", count ( p ) ) ;
delete ( &p, 99 ) ;
delete ( &p, 1 ) ;
delete ( &p, 10 ) ;
display ( p ) ;
printf ( "\nNo. of elements in the Linked List = %d", count ( p ) ) ;
}
/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
struct node *temp, *r ;
if ( *q == NULL ) /* if the list is empty, create first node */
{
temp = malloc ( sizeof ( struct node ) ) ;
temp -> data = num ;
temp -> link = NULL ;
*q = temp ;
}
else
{
temp = *q ;
/* go to last node */
while ( temp -> link != NULL )
temp = temp -> link ;
/* add node at the end */
r = malloc ( sizeof ( struct node ) ) ;
r -> data = num ;
r -> link = NULL ;
temp -> link = r ;
}
}
/* adds a new node at the beginning of the linked list */
void addatbeg ( struct node **q, int num )
{
struct node *temp ;
/* add new node */
temp = malloc ( sizeof ( struct node ) ) ;
temp -> data = num ;
temp -> link = *q ;
*q = temp ;
}
/* adds a new node after the specified number of nodes */
void addafter ( struct node *q, int loc, int num )
{
struct node *temp, *r ;
int i ;
temp = q ;
/* skip to desired portion */
for ( i = 0 ; i < loc ; i++ )
{
temp = temp -> link ;
/* if end of linked list is encountered */
if ( temp == NULL )
{
printf ( "\nThere are less than %d elements in list", loc ) ;
return ;
}
}
/* insert new node */
r = malloc ( sizeof ( struct node ) ) ;
r -> data = num ;
r -> link = temp -> link ;
temp -> link = r ;
}
/* displays the contents of the linked list */
void display ( struct node *q )
{
printf ( "\n" ) ;
/* traverse the entire linked list */
while ( q != NULL )
{
printf ( "%d ", q -> data ) ;
q = q -> link ;
}
}
/* counts the number of nodes present in the linked list */
int count ( struct node * q )
{
int c = 0 ;
/* traverse the entire linked list */
while ( q != NULL )
{
q = q -> link ;
c++ ;
}
return c ;
}
/* deletes the specified node from the linked list */
void delete ( struct node **q, int num )
{
struct node *old, *temp ;
temp = *q ;
while ( temp != NULL )
{
if ( temp -> data == num )
{
/* if node to be deleted is the first node in the linked list */
if ( temp == *q )
*q = temp -> link ;
/* deletes the intermediate nodes in the linked list */
else
old -> link = temp -> link ;
/* free the memory occupied by the node */
free ( temp ) ;
return ;
}
/* traverse the linked list till the last node is reached */
else
{
old = temp ; /* old points to the previous node */
temp = temp -> link ; /* go to the next node */
}
}
printf ( "\nElement %d not found", num ) ;
}

DataStructure Program to maintain a heap

#include <stdio.h>
#include <conio.h>
void restoreup ( int, int * ) ;
void restoredown ( int, int *, int ) ;
void makeheap ( int *, int ) ;
void add ( int, int *, int * ) ;
int replace ( int, int *, int ) ;
int del ( int *, int * ) ;
void main( )
{
int arr [20] = { 1000, 7, 10, 25, 17, 23, 27, 16, 19, 37, 42, 4, 33, 1, 5, 11 } ;
int i, n = 15 ;
clrscr( ) ;
makeheap ( arr, n ) ;
printf ( "Heap:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;
i = 24 ;
add ( i, arr, &n ) ;
printf ( "\n\nElement added %d.\n", i ) ;
printf ( "\nHeap after addition of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;
i = replace ( 2, arr, n ) ;
printf ( "\n\nElement replaced %d.\n", i ) ;
printf ( "\nHeap after replacement of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;
i = del ( arr, &n ) ;
printf ( "\n\nElement deleted %d.\n", i ) ;
printf ( "\nHeap after deletion of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;
getch( ) ;
}
void restoreup ( int i, int *arr )
{
int val ;
val = arr [i] ;
while ( arr [i / 2] <= val )
{
arr [i] = arr [i / 2] ;
i = i / 2 ;
}
arr [i] = val ;
}
void restoredown ( int pos, int *arr, int n )
{
int i, val ;
val = arr [pos] ;
while ( pos <= n / 2 )
{
i = 2 * pos ;
if ( ( i < n ) && ( arr [i] < arr [i + 1] ) )
i++ ;
if ( val >= arr [i] )
break ;
arr [pos] = arr [i] ;
pos = i ;
}
arr [pos] = val ;
}
void makeheap ( int *arr, int n )
{
int i ;
for ( i = n / 2 ; i >= 1 ; i-- )
restoredown ( i, arr, n ) ;
}
void add ( int val, int *arr, int *n )
{
( *n ) ++ ;
arr [*n] = val ;
restoreup ( *n, arr ) ;
}
int replace ( int i, int *arr, int n )
{
int r = arr [1] ;
arr [1] = i ;
for ( i = n / 2 ; i >= 1 ; i-- )
restoredown ( i, arr, n ) ;
return r ;
}
int del ( int *arr, int *n )
{
int val ;
val = arr [1] ;
arr [1] = arr [*n] ;
( *n ) -- ;
restoredown ( 1, arr, *n ) ;
return val ;
}

DataStructure Program to implement a binary search tree

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
struct btreenode
{
struct btreenode *leftchild ;
int data ;
struct btreenode *rightchild ;
} ;
void insert ( struct btreenode **, int ) ;
void inorder ( struct btreenode * ) ;
void preorder ( struct btreenode * ) ;
void postorder ( struct btreenode * ) ;
void main( )
{
struct btreenode *bt ;
int req, i = 1, num ;
bt = NULL ; /* empty tree */
clrscr( ) ;
printf ( "Specify the number of items to be inserted: " ) ;
scanf ( "%d", &req ) ;
while ( i++ <= req )
{
printf ( "Enter the data: " ) ;
scanf ( "%d", &num ) ;
insert ( &bt, num ) ;
}
printf ( "\nIn-order Traversal: " ) ;
inorder ( bt ) ;
printf ( "\nPre-order Traversal: " ) ;
preorder ( bt ) ;
printf ( "\nPost-order Traversal: " ) ;
postorder ( bt ) ;
}
/* inserts a new node in a binary search tree */
void insert ( struct btreenode **sr, int num )
{
if ( *sr == NULL )
{
*sr = malloc ( sizeof ( struct btreenode ) ) ;
( *sr ) -> leftchild = NULL ;
( *sr ) -> data = num ;
( *sr ) -> rightchild = NULL ;
return ;
}
else /* search the node to which new node will be attached */
{
/* if new data is less, traverse to left */
if ( num < ( *sr ) -> data )
insert ( &( ( *sr ) -> leftchild ), num ) ;
else
/* else traverse to right */
insert ( &( ( *sr ) -> rightchild ), num ) ;
}
return ;
}
/* traverse a binary search tree in a LDR (Left-Data-Right) fashion */
void inorder ( struct btreenode *sr )
{
if ( sr != NULL )
{
inorder ( sr -> leftchild ) ;
/* print the data of the node whose leftchild is NULL or the path has already been traversed */
printf ( "\t%d", sr -> data ) ;
inorder ( sr -> rightchild ) ;
}
else
return ;
}
/* traverse a binary search tree in a DLR (Data-Left-right) fashion */
void preorder ( struct btreenode *sr )
{
if ( sr != NULL )
{
/* print the data of a node */
printf ( "\t%d", sr -> data ) ;
/* traverse till leftchild is not NULL */
preorder ( sr -> leftchild ) ;
/* traverse till rightchild is not NULL */
preorder ( sr -> rightchild ) ;
}
else
return ;
}
/* traverse a binary search tree in LRD (Left-Right-Data) fashion */
void postorder ( struct btreenode *sr )
{
if ( sr != NULL )
{
postorder ( sr -> leftchild ) ;
postorder ( sr -> rightchild ) ;
printf ( "\t%d", sr -> data ) ;
}
else
return ;
}

DataStructure Program to find the number of nodes in the linked list using recursion

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure containing a data part and link part */
struct node
{
int data ;
struct node *link ;
} ;
void append ( struct node **, int ) ;
int length ( struct node * ) ;
void main( )
{
struct node *p ;
p = NULL ; /* empty linked list */
append ( &p, 1 ) ;
append ( &p, 2 ) ;
append ( &p, 3 ) ;
append ( &p, 4 ) ;
append ( &p, 5 ) ;
clrscr( ) ;
printf ( "Length of linked list = %d", length ( p ) ) ;
}
/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
struct node *temp ;
temp = *q ;
if ( *q == NULL ) /* if the list is empty, create first node */
{
*q = malloc ( sizeof ( struct node ) ) ;
temp = *q ;
}
else
{
/* go to last node */
while ( temp -> link != NULL )
temp = temp -> link ;
/* add node at the end */
temp -> link = malloc ( sizeof ( struct node ) ) ;
temp = temp -> link ;
}
/* assign data to the last node */
temp -> data = num ;
temp -> link = NULL ;
}
/* counts the number of nodes in a linked list */
int length ( struct node *q )
{
static int l ;
/* if list is empty or if NULL is encountered */
if ( q == NULL )
return ( 0 ) ;
else
{
/* go to next node */
l = 1 + length ( q -> link ) ;
return ( l ) ;
}
}

DataStructure Program to evaluate an epression entered in postfix form

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#define MAX 50
struct postfix
{
int stack[MAX] ;
int top, nn ;
char *s ;
} ;
void initpostfix ( struct postfix * ) ;
void setexpr ( struct postfix *, char * ) ;
void push ( struct postfix *, int ) ;
int pop ( struct postfix * ) ;
void calculate ( struct postfix * ) ;
void show ( struct postfix ) ;
void main( )
{
struct postfix q ;
char expr[MAX] ;
clrscr( ) ;
initpostfix ( &q ) ;
printf ( "\nEnter postfix expression to be evaluated: " ) ;
gets ( expr ) ;
setexpr ( &q, expr ) ;
calculate ( &q ) ;
show ( q ) ;
getch( ) ;
}
/* initializes data members */
void initpostfix ( struct postfix *p )
{
p -> top = -1 ;
}
/* sets s to point to the given expr. */
void setexpr ( struct postfix *p, char *str )
{
p -> s = str ;
}
/* adds digit to the stack */
void push ( struct postfix *p, int item )
{
if ( p -> top == MAX - 1 )
printf ( "\nStack is full." ) ;
else
{
p -> top++ ;
p -> stack[p -> top] = item ;
}
}
/* pops digit from the stack */
int pop ( struct postfix *p )
{
int data ;
if ( p -> top == -1 )
{
printf ( "\nStack is empty." ) ;
return NULL ;
}
data = p -> stack[p -> top] ;
p -> top-- ;
return data ;
}
/* evaluates the postfix expression */
void calculate( struct postfix *p )
{
int n1, n2, n3 ;
while ( *( p -> s ) )
{
/* skip whitespace, if any */
if ( *( p -> s ) == ' ' || *( p -> s ) == '\t' )
{
p -> s++ ;
continue ;
}
/* if digit is encountered */
if ( isdigit ( *( p -> s ) ) )
{
p -> nn = *( p -> s ) - '0' ;
push ( p, p -> nn ) ;
}
else
{
/* if operator is encountered */
n1 = pop ( p ) ;
n2 = pop ( p ) ;
switch ( *( p -> s ) )
{
case '+' :
n3 = n2 + n1 ;
break ;
case '-' :
n3 = n2 - n1 ;
break ;
case '/' :
n3 = n2 / n1 ;
break ;
case '*' :
n3 = n2 * n1 ;
break ;
case '%' :
n3 = n2 % n1 ;
break ;
case '$' :
n3 = pow ( n2 , n1 ) ;
break ;
default :
printf ( "Unknown operator" ) ;
exit ( 1 ) ;
}
push ( p, n3 ) ;
}
p -> s++ ;
}
}
/* displays the result */
void show ( struct postfix p )
{
p.nn = pop ( &p ) ;
printf ( "Result is: %d", p.nn ) ;
}

DataStructure Program to create a 3-tuple from a given matrix

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
#define MAX1 3
#define MAX2 3
struct sparse
{
int *sp ;
int row ;
} ;
void initsparse ( struct sparse * ) ;
void create_array ( struct sparse * ) ;
void display ( struct sparse ) ;
int count ( struct sparse ) ;
void create_tuple ( struct sparse *, struct sparse ) ;
void display_tuple ( struct sparse ) ;
void delsparse ( struct sparse * ) ;
void main( )
{
struct sparse s1, s2 ;
int c ;
clrscr( );
initsparse ( &s1 ) ;
initsparse ( &s2 ) ;
create_array ( &s1 ) ;
printf ( "\nElements in Sparse Matrix: " ) ;
display ( s1 ) ;
c = count ( s1 ) ;
printf ( "\n\nNumber of non-zero elements: %d", c ) ;
create_tuple ( &s2, s1 ) ;
printf ( "\n\nArray of non-zero elements: " ) ;
display_tuple ( s2 ) ;
delsparse ( &s1 ) ;
delsparse ( &s2 ) ;
getch( ) ;
}
/* initialises element of structure */
void initsparse ( struct sparse *p )
{
p -> sp = NULL ;
}
/* dynamically creates the matrix of size MAX1 x MAX2 */
void create_array ( struct sparse *p )
{
int n, i ;
p -> sp = ( int * ) malloc ( MAX1 * MAX2 * sizeof ( int ) ) ;
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
printf ( "Enter element no. %d: ", i ) ;
scanf ( "%d", &n ) ;
* ( p -> sp + i ) = n ;
}
}
/* displays the contents of the matrix */
void display ( struct sparse p )
{
int i ;
/* traverses the entire matrix */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
/* positions the cursor to the new line for every new row */
if ( i % MAX2 == 0 )
printf ( "\n" ) ;
printf ( "%d\t", * ( p.sp + i ) ) ;
}
}
/* counts the number of non-zero elements */
int count ( struct sparse p )
{
int cnt = 0, i ;
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
if ( * ( p.sp + i ) != 0 )
cnt++ ;
}
return cnt ;
}
/* creates an array that stores information about non-zero elements */
void create_tuple ( struct sparse *p, struct sparse s )
{
int r = 0 , c = -1, l = -1, i ;
p -> row = count ( s ) + 1 ;
p -> sp = ( int * ) malloc ( p -> row * 3 * sizeof ( int ) ) ;
* ( p -> sp + 0 ) = MAX1 ;
* ( p -> sp + 1 ) = MAX2 ;
* ( p -> sp + 2 ) = p -> row - 1 ;
l = 2 ;
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
c++ ;
/* sets the row and column values */
if ( ( ( i % MAX2 ) == 0 ) && ( i != 0 ) )
{
r++ ;
c = 0 ;
}
/* checks for non-zero element row, column and non-zero element value is assigned to the matrix */
if ( * ( s.sp + i ) != 0 )
{
l++ ;
* ( p -> sp + l ) = r ;
l++ ;
* ( p -> sp + l ) = c ;
l++ ;
* ( p -> sp + l ) = * ( s.sp + i ) ;
}
}
}
/* displays the contents of 3-tuple */
void display_tuple ( struct sparse p )
{
int i ;
for ( i = 0 ; i < p.row * 3 ; i++ )
{
if ( i % 3 == 0 )
printf ( "\n" ) ;
printf ( "%d\t", * ( p.sp + i ) ) ;
}
}
/* deallocates memory */
void delsparse ( struct sparse *p )
{ free ( p -> sp ) ;
}

DataStructure Program to convert expression in postfix form to prefix form

#include <stdio.h>
#include <conio.h>
#include <string.h>
#define MAX 50
struct postfix
{
char stack[MAX][MAX], target[MAX] ;
char temp1[2], temp2[2] ;
char str1[MAX], str2[MAX], str3[MAX] ;
int i, top ;
} ;
void initpostfix ( struct postfix * ) ;
void setexpr ( struct postfix *, char * ) ;
void push ( struct postfix *, char * ) ;
void pop ( struct postfix *, char * ) ;
void convert ( struct postfix * ) ;
void show ( struct postfix ) ;
void main( )
{
struct postfix q ;
char expr[MAX] ;
clrscr( ) ;
initpostfix ( &q ) ;
printf ( "\nEnter an expression in postfix form: " ) ;
gets ( expr ) ;
setexpr ( &q, expr ) ;
convert ( &q ) ;
printf ( "\nThe Prefix expression is: " ) ;
show ( q ) ;
getch( ) ;
}
/* initializes the elements of the structure */
void initpostfix ( struct postfix *p )
{
p -> i = 0 ;
p -> top = -1 ;
strcpy ( p -> target, "" ) ;
}
/* copies given expr. to target string */
void setexpr ( struct postfix *p, char *c )
{
strcpy ( p -> target, c ) ;
}
/* adds an operator to the stack */
void push ( struct postfix *p, char *str )
{
if ( p -> top == MAX - 1 )
printf ( "\nStack is full." ) ;
else
{
p -> top++ ;
strcpy ( p -> stack[p -> top], str ) ;
}
}
/* pops an element from the stack */
void pop ( struct postfix *p, char *a )
{
if ( p -> top == -1 )
printf ( "\nStack is empty." ) ;
else
{
strcpy ( a, p -> stack[p -> top] ) ;
p -> top-- ;
}
}
/* converts given expr. to prefix form */
void convert ( struct postfix *p )
{
while ( p -> target[p -> i] != '\0' )
{
/* skip whitespace, if any */
if ( p -> target[p -> i] == ' ')
p -> i++ ;
if( p -> target[p -> i] == '%' || p -> target[p -> i] == '*' || p -> target[p -> i] == '-' || p -> target[p -> i] == '+' || p -> target[p -> i] == '/' || p -> target[p -> i] == '$' )
{
pop ( p, p -> str2 ) ;
pop ( p, p -> str3 ) ;
p -> temp1[0] = p -> target[ p -> i] ;
p -> temp1[1] = '\0' ;
strcpy ( p -> str1, p -> temp1 ) ;
strcat ( p -> str1, p -> str3 ) ;
strcat ( p -> str1, p -> str2 ) ;
push ( p, p -> str1 ) ;
}
else
{
p -> temp1[0] = p -> target[p -> i] ;
p -> temp1[1] = '\0' ;
strcpy ( p -> temp2, p -> temp1 ) ;
push ( p, p -> temp2 ) ;
}
p -> i++ ;
}
}
/* displays the prefix form of expr. */
void show ( struct postfix p )
{
char *temp = p.stack[0] ;
while ( *temp )
{
printf ( "%c ", *temp ) ;
temp++ ;
}
}

DataStructure Program to copy one linked list into another using recursion

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
/* structure containing a data part and link part */
struct node
{
int data ;
struct node *link ;
} ;
void append ( struct node **, int ) ;
void copy ( struct node *, struct node ** ) ;
void display ( struct node * ) ;
void main( )
{
struct node *first, *second ;
first = second = NULL ; /* empty linked lists */
append ( &first, 1 ) ;
append ( &first, 2 ) ;
append ( &first, 3 ) ;
append ( &first, 4 ) ;
append ( &first, 5 ) ;
append ( &first, 6 ) ;
append ( &first, 7 ) ;
clrscr( ) ;
display ( first ) ;
copy ( first, &second ) ;
display ( second ) ;
}
/* adds a node at the end of the linked list */
void append ( struct node **q, int num )
{
struct node *temp ;
temp = *q ;
if ( *q == NULL ) /* if the list is empty, create first node */
{
*q = malloc ( sizeof ( struct node ) ) ;
temp = *q ;
}
else
{
/* go to last node */
while ( temp -> link != NULL )
temp = temp -> link ;
/* add node at the end */
temp -> link = malloc ( sizeof ( struct node ) ) ;
temp = temp -> link ;
}
/* assign data to the last node */
temp -> data = num ;
temp -> link = NULL ;
}
/* copies a linked list into another */
void copy ( struct node *q, struct node **s )
{
if ( q != NULL )
{
*s = malloc ( sizeof ( struct node ) ) ;
( *s ) -> data = q -> data ;
( *s ) -> link = NULL ;
copy ( q -> link, &( ( *s ) -> link ) ) ;
}
}
/* displays the contents of the linked list */
void display ( struct node *q )
{
printf ( "\n" ) ;
/* traverse the entire linked list */
while ( q != NULL )
{
printf ( "%d ", q -> data ) ;
q = q -> link ;
}
}

DataStructure Program to convert expression in postfix form to prefix form

DataStructure Program to convert an expression in postfix form to an infix form

#include <stdio.h>
#include <conio.h>
#include <string.h>
#define MAX 50
struct postfix
{
char stack[MAX][MAX], target[MAX] ;
char temp1[2], temp2[2] ;
char str1[MAX], str2[MAX], str3[MAX] ;
int i, top ;
} ;
void initpostfix ( struct postfix * ) ;
void setexpr ( struct postfix *, char * ) ;
void push ( struct postfix *, char * ) ;
void pop ( struct postfix *, char * ) ;
void convert ( struct postfix * ) ;
void show ( struct postfix ) ;
void main( )
{
struct postfix q ;
char expr[MAX] ;
clrscr( ) ;
initpostfix ( &q ) ;
printf ( "\nEnter an expression in postfix form: " ) ;
gets ( expr ) ;
setexpr ( &q, expr ) ;
convert ( &q ) ;
printf ( "\nThe infix expression is: " ) ;
show ( q ) ;
getch( ) ;
}
/* initializes data member */
void initpostfix ( struct postfix *p )
{
p -> i = 0 ;
p -> top = -1 ;
strcpy ( p -> target, "" ) ;
}
/* copies given expression to target string */
void setexpr ( struct postfix *p, char *c )
{
strcpy ( p -> target, c ) ;
}
/* adds an expr. to the stack */
void push ( struct postfix *p, char *str )
{
if ( p -> top == MAX - 1 )
printf ( "\nStack is full." ) ;
else
{
p -> top++ ;
strcpy ( p -> stack[p -> top], str ) ;
}
}
/* pops an expr. from the stack */
void pop ( struct postfix *p, char *a )
{
if ( p -> top == -1 )
printf ( "\nStack is empty." ) ;
else
{
strcpy ( a, p -> stack[p -> top] ) ;
p -> top-- ;
}
}
/* converts given expr. to infix form */
void convert ( struct postfix *p )
{
while ( p -> target[p -> i] )
{
/* skip whitespace, if any */
if( p -> target[p -> i] == ' ' )
p -> i++ ;
if ( p -> target[p -> i] == '%' || p -> target[p -> i] == '*' || p -> target[p -> i] == '-' || p -> target[p -> i] == '+' || p -> target[p -> i] == '/' || p -> target[p -> i] == '$' )
{
pop ( p, p -> str2 ) ;
pop ( p, p -> str3 ) ;
p -> temp1[0] = p -> target[p -> i] ;
p -> temp1[1] = '\0' ;
strcpy ( p -> str1, p -> str3 ) ;
strcat ( p -> str1, p -> temp1 ) ;
strcat ( p -> str1, p -> str2 ) ;
push ( p, p -> str1 ) ;
}
else
{
p -> temp1[0] = p -> target[p -> i] ;
p -> temp1[1] = '\0' ;
strcpy ( p -> temp2, p -> temp1 ) ;
push ( p, p -> temp2 ) ;
}
p -> i++ ;
}
}
/* displays the expression */
void show ( struct postfix p )
{
char *t ;
t = p.stack[0] ;
while ( *t )
{
printf ( "%c ", *t ) ;
t++ ;
}
}

DataStructure Program to compare two linked lists using recursion

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
struct node
{
int data ;
struct node *link ;
} ;
void append ( struct node **, int ) ;
int compare ( struct node *, struct node * ) ;
void main( )
{
struct node *first, *second ;
first = second = NULL ; /* empty linked lists */
append ( &first, 1 ) ;
append ( &first, 2 ) ;
append ( &first, 3 ) ;
append ( &second, 1 ) ;
append ( &second, 2 ) ;
append ( &second, 3 ) ;
clrscr( ) ;
if ( compare ( first, second ) )
printf ( "Both linked lists are EQUAL" ) ;
else
printf ( "Linked lists are DIFFERENT" ) ;
}
/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
struct node *temp ;
temp = *q ;
if ( *q == NULL ) /* if the list is empty, create first node */
{
*q = malloc ( sizeof ( struct node ) ) ;
temp = *q ;
}
else
{
/* go to last node */
while ( temp -> link != NULL )
temp = temp -> link ;
/* add node at the end */
temp -> link = malloc ( sizeof ( struct node ) ) ;
temp = temp -> link ;
}
/* assign data to the last node */
temp -> data = num ;
temp -> link = NULL ;
}
/* compares 2 linked lists and returns 1 if linked lists are equal and 0 if unequal */
int compare ( struct node *q, struct node *r )
{
static int flag ;
if ( ( q == NULL ) && ( r == NULL ) )
flag = 1 ;
else
{
if ( q == NULL || r == NULL )
flag = 0 ;
if ( q -> data != r -> data )
flag = 0 ;
else
compare ( q -> link, r -> link ) ;
}
return ( flag ) ;
}

DataStructure Program for Quick sort

#include <stdio.h>
#include <conio.h>
int split ( int*, int, int ) ;
void main( )
{
int arr[10] = { 11, 2, 9, 13, 57, 25, 17, 1, 90, 3 } ;
int i ;
void quicksort ( int *, int, int ) ;
clrscr( ) ;
printf ( "Quick sort.\n" ) ;
printf ( "\nArray before sorting:\n") ;
for ( i = 0 ; i <= 9 ; i++ )
printf ( "%d\t", arr[i] ) ;
quicksort ( arr, 0, 9 ) ;
printf ( "\nArray after sorting:\n") ;
for ( i = 0 ; i <= 9 ; i++ )
printf ( "%d\t", arr[i] ) ;
getch( ) ;
}
void quicksort ( int a[ ], int lower, int upper )
{
int i ;
if ( upper > lower )
{
i = split ( a, lower, upper ) ;
quicksort ( a, lower, i - 1 ) ;
quicksort ( a, i + 1, upper ) ;
}
}
int split ( int a[ ], int lower, int upper )
{
int i, p, q, t ;
p = lower + 1 ;
q = upper ;
i = a[lower] ;
while ( q >= p )
{
while ( a[p] < i )
p++ ;
while ( a[q] > i )
q-- ;
if ( q > p )
{
t = a[p] ;
a[p] = a[q] ;
a[q] = t ;
}
}
t = a[lower] ;
a[lower] = a[q] ;
a[q] = t ;
return q ;
}

DataStructure Program for Merge Sort

#include <stdio.h>
#include <conio.h>
void main( )
{
int a[5] = { 11, 2, 9, 13, 57 } ;
int b[5] = { 25, 17, 1, 90, 3 } ;
int c[10] ;
int i, j, k, temp ;
clrscr( ) ;
printf ( "Merge sort.\n" ) ;
printf ( "\nFirst array:\n" ) ;
for ( i = 0 ; i <= 4 ; i++ )
printf ( "%d\t", a[i] ) ;
printf ( "\n\nSecond array:\n" ) ;
for ( i = 0 ; i <= 4 ; i++ )
printf ( "%d\t", b[i] ) ;
for ( i = 0 ; i <= 3 ; i++ )
{
for ( j = i + 1 ; j <= 4 ; j++ )
{
if ( a[i] > a[j] )
{
temp = a[i] ;
a[i] = a[j] ;
a[j] = temp ;
}
if ( b[i] > b[j] )
{
temp = b[i] ;
b[i] = b[j] ;
b[j] = temp ;
}
}
}
for ( i = j = k = 0 ; i <= 9 ; )
{
if ( a[j] <= b[k] )
c[i++] = a[j++] ;
else
c[i++] = b[k++] ;
if ( j == 5 || k == 5 )
break ;
}
for ( ; j <= 4 ; )
c[i++] = a[j++] ;
for ( ; k <= 4 ; )
c[i++] = b[k++] ;
printf ( "\n\nArray after sorting:\n") ;
for ( i = 0 ; i <= 9 ; i++ )
printf ( "%d\t", c[i] ) ;
getch( ) ;
}

DataStructure Program to check for the entered name in the master list

#include <stdio.h>
#include <conio.h>
#include <string.h>
#define MAX1 6
#define MAX2 10
char masterlist[MAX1][MAX2] ;
int count ;
int add ( char *s ) ;
int find ( char *s ) ;
void main( )
{
char yourname[MAX2] ;
int flag ;
clrscr( ) ;
flag = add ( "akshay" ) ;
if ( flag == 0 )
printf ( "\nUnable to add string" ) ;
flag = add ( "parag" ) ;
if ( flag == 0 )
printf ( "\nUnable to add string" ) ;
flag = add ( "raman" ) ;
if ( flag == 0 )
printf ( "\nUnable to add string" ) ;
flag = add ( "srinivas" ) ;
if ( flag == 0 )
printf ( "\nUnable to add string" ) ;
flag = add ( "gopal" ) ;
if ( flag == 0 )
printf ( "\nUnable to add string" ) ;
flag = add ( "rajesh" ) ;
if ( flag == 0 )
printf ( "Unable to add string" ) ;
printf ( "Enter your name: " ) ;
gets ( yourname ) ;
flag = find ( yourname ) ;
if ( flag == 1 )
printf ( "Welcome, you can enter the palace\n" ) ;
else
printf ( "Sorry, you are a trespasser" ) ;
getch( ) ;
}
/* adds string to the array */
int add ( char *s )
{
if ( count < MAX1 )
{
if ( strlen ( s ) < MAX2 )
{
strcpy ( &masterlist[count][0], s ) ;
count++ ;
return 1 ;
}
}
return 0 ;
}
/* finds the given string */
int find ( char *s )
{
int flag = 0, i ;
for ( i = 0 ; i < count ; i++ )
{
if ( strcmp ( &masterlist[i][0], s ) == 0 )
{
flag = 1 ;
break ;
}
}
return flag ;
}

DataStructure Program to build a binary search tree from arrays

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
struct node
{
struct node *left ;
char data ;
struct node *right ;
} ;
struct node * buildtree ( int ) ;
void inorder ( struct node * ) ;
char arr[ ] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', '\0', '\0', 'H' } ;
int lc[ ] = { 1, 3, 5, -1, 9, -1, -1, -1, -1, -1 } ;
int rc[ ] = { 2, 4, 6, -1, -1, -1, -1, -1, -1, -1 } ;
void main( )
{
struct node *root ;
clrscr( ) ;
root = buildtree ( 0 ) ;
printf ( �In-order Traversal:\n� ) ;
inorder ( root ) ;
getch( ) ;
}
struct node * buildtree ( int index )
{
struct node *temp = NULL ;
if ( index != -1 )
{
temp = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
temp -> left = buildtree ( lc[index] ) ;
temp -> data = arr[index] ;
temp -> right = buildtree ( rc[index] ) ;
}
return temp ;
}
void inorder ( struct node *root )
{
if ( root != NULL )
{
inorder ( root -> left ) ;
printf ( "%c\t", root -> data ) ;
inorder ( root -> right ) ;
}
}

DataStructure Program to allocate memory dynamically

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
#include <string.h>
void main( )
{
char *name[5] ;
char str[20] ;
int i ;
clrscr( ) ;
for ( i = 0 ; i < 5 ; i++ )
{
printf ( "Enter a String: " ) ;
gets ( str ) ;
name[i] = ( char * ) malloc ( strlen ( str ) + 1 ) ;
strcpy ( name[i], str ) ;
}
printf ( "\nThe strings are:" ) ;
for ( i = 0 ; i < 5 ; i++ )
printf ( "\n%s", name[i] ) ;
for ( i = 0 ; i < 5 ; i++ )
free ( name[i] ) ;
getch( ) ;
}

DataStructure Program to add two sparse matrices

#include <stdio.h>
#include <conio.h>
#include <alloc.h>
#define MAX1 3
#define MAX2 3
#define MAXSIZE 9
#define BIGNUM 100
struct sparse
{
int *sp ;
int row ;
int *result ;
} ;
void initsparse ( struct sparse * ) ;
void create_array ( struct sparse * ) ;
int count ( struct sparse ) ;
void display ( struct sparse ) ;
void create_tuple ( struct sparse *, struct sparse ) ;
void display_tuple ( struct sparse ) ;
void addmat ( struct sparse *, struct sparse, struct sparse ) ;
void display_result ( struct sparse ) ;
void delsparse ( struct sparse * ) ;
void main( )
{
struct sparse s[5] ;
int i ;
clrscr( ) ;
for ( i = 0 ; i <= 4 ; i++ )
initsparse ( &s[i] ) ;
create_array ( &s[0] ) ;
create_tuple ( &s[1], s[0] ) ;
display_tuple ( s[1] ) ;
create_array ( &s[2] ) ;
create_tuple ( &s[3], s[2] ) ;
display_tuple ( s[3] ) ;
addmat ( &s[4], s[1], s[3] ) ;
printf ( "\nResult of addition of two matrices: " ) ;
display_result ( s[4] ) ;
for ( i = 0 ; i <= 4 ; i++ )
delsparse ( &s[i] ) ;
getch( ) ;
}
/* initialises structure elements */
void initsparse ( struct sparse *p )
{
p -> sp = NULL ;
p -> result = NULL ;
}
/* dynamically creates the matrix */
void create_array ( struct sparse *p )
{
int n, i ;
/* allocate memory */
p -> sp = ( int * ) malloc ( MAX1 * MAX2 * sizeof ( int ) ) ;
/* add elements to the array */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
printf ( "Enter element no. %d:", i ) ;
scanf ( "%d", &n ) ;
* ( p -> sp + i ) = n ;
}
}
/* displays the contents of the matrix */
void display ( struct sparse s )
{
int i ;
/* traverses the entire matrix */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
/* positions the cursor to the new line for every new row */
if ( i % MAX2 == 0 )
printf ( "\n" ) ;
printf ( "%d\t", * ( s.sp + i ) ) ;
}
}
/* counts the number of non-zero elements */
int count ( struct sparse s )
{
int cnt = 0, i ;
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
if ( * ( s.sp + i ) != 0 )
cnt++ ;
}
return cnt ;
}
/* creates an array that stores information about non-zero elements */
void create_tuple ( struct sparse *p, struct sparse s )
{
int r = 0 , c = -1, l = -1, i ;
/* get the total number of non-zero elements
and add 1 to store total no. of rows, cols, and non-zero values */
p -> row = count ( s ) + 1 ;
/* allocate memory */
p -> sp = ( int * ) malloc ( p -> row * 3 * sizeof ( int ) ) ;
/* store information about
total no. of rows, cols, and non-zero values */
* ( p -> sp + 0 ) = MAX1 ;
* ( p -> sp + 1 ) = MAX2 ;
* ( p -> sp + 2 ) = p -> row - 1 ;
l = 2 ;
/* scan the array and store info. about non-zero values in the 3-tuple */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ )
{
c++ ;
/* sets the row and column values */
if ( ( ( i % MAX2 ) == 0 ) && ( i != 0 ) )
{
r++ ;
c = 0 ;
}
/* checks for non-zero element row, column and non-zero element value is assigned to the matrix */
if ( * ( s.sp + i ) != 0 )
{
l++ ;
* ( p -> sp + l ) = r ;
l++ ;
* ( p -> sp + l ) = c ;
l++ ;
* ( p -> sp + l ) = * ( s.sp + i ) ;
}
}
}
/* displays the contents of the matrix */
void display_tuple ( struct sparse s )
{
int i, j ;
/* traverses the entire matrix */
printf ( "\nElements in a 3-tuple: \n" ) ;
j = ( * ( s.sp + 2 ) * 3 ) + 3 ;
for ( i = 0 ; i < j ; i++ )
{
/* positions the cursor to the new line for every new row */
if ( i % 3 == 0 )
printf ( "\n" ) ;
printf ( "%d\t", * ( s.sp + i ) ) ;
}
printf ( "\n" ) ;
}
/* carries out addition of two matrices */
void addmat ( struct sparse *p, struct sparse s1, struct sparse s2 )
{
int i = 1, j = 1, k = 1 ;
int elem = 1 ;
int max, amax, bmax ;
int rowa, rowb, cola, colb, vala, valb ;
/* get the total number of non-zero values from both the matrices */
amax = * ( s1.sp + 2 ) ;
bmax = * ( s2.sp + 2 ) ;
max = amax + bmax ;
/* allocate memory for result */
p -> result = ( int * ) malloc ( MAXSIZE * 3 * sizeof ( int ) ) ;
while ( elem <= max )
{
/* check if i < max. non-zero values
in first 3-tuple and get the values */
if ( i <= amax )
{
rowa = * ( s1.sp + i * 3 + 0 ) ;
cola = * ( s1.sp + i * 3 + 1 ) ;
vala = * ( s1.sp + i * 3 + 2 ) ;
}
else
rowa = cola = BIGNUM ;
/* check if j < max. non-zero values in secon 3-tuple and get the values */
if ( j <= bmax )
{
rowb = * ( s2.sp + j * 3 + 0 ) ;
colb = * ( s2.sp + j * 3 + 1 ) ;
valb = * ( s2.sp + j * 3 + 2 ) ;
}
else
rowb = colb = BIGNUM ;
/* if row no. of both 3-tuple are same */
if ( rowa == rowb )
{
/* if col no. of both 3-tuple are same */
if ( cola == colb )
{
/* add tow non-zero values
store in result */
* ( p -> result + k * 3 + 0 ) = rowa ;
* ( p -> result + k * 3 + 1 ) = cola ;
* ( p -> result + k * 3 + 2 ) = vala + valb ;
i++ ;
j++ ;
max-- ;
}
/* if col no. of first 3-tuple is < col no. of second 3-tuple, then add info. as it is to result */
if ( cola < colb )
{
* ( p -> result + k * 3 + 0 ) = rowa ;
* ( p -> result + k * 3 + 1 ) = cola ;
* ( p -> result + k * 3 + 2 ) = vala ;
i++ ;
}
/* if col no. of first 3-tuple is > col no. of second 3-tuple, then add info. as it is to result */
if ( cola > colb )
{
* ( p -> result + k * 3 + 0 ) = rowb ;
* ( p -> result + k * 3 + 1 ) = colb ;
* ( p -> result + k * 3 + 2 ) = valb ;
j++ ;
}
k++ ;
}
/* if row no. of first 3-tuple is < row no. of second 3-tuple, then add info. as it is to result */
if ( rowa < rowb )
{
* ( p -> result + k * 3 + 0 ) = rowa ;
* ( p -> result + k * 3 + 1 ) = cola ;
* ( p -> result + k * 3 + 2 ) = vala ;
i++ ;
k++ ;
}
/* if row no. of first 3-tuple is > row no. of second 3-tuple, then add info. as it is to result */
if ( rowa > rowb )
{
* ( p -> result + k * 3 + 0 ) = rowb ;
* ( p -> result + k * 3 + 1 ) = colb ;
* ( p -> result + k * 3 + 2 ) = valb ;
j++ ;
k++ ;
}
elem++ ;
}
/* add info about the total no. of rows, cols, and non-zero values that the resultant array contains to the result */
* ( p -> result + 0 ) = MAX1 ;
* ( p -> result + 1 ) = MAX2 ;
* ( p -> result + 2 ) = max ;
}
/* displays the contents of the matrix */
void display_result ( struct sparse s )
{
int i ;
/* traverses the entire matrix */
for ( i = 0 ; i < ( * ( s.result + 0 + 2 ) + 1 ) * 3 ; i++ )
{
/* positions the cursor to the new line for every new row */
if ( i % 3 == 0 )
printf ( "\n" ) ;
printf ( "%d\t", * ( s.result + i ) ) ;
}
}
/* deallocates memory */
void delsparse ( struct sparse *p )
{
if ( p -> sp != NULL )
free ( p -> sp ) ;
if ( p -> result != NULL )
free ( p -> result ) ;
}