DataStructure Program to perform basic operations on string

#include <stdio.h>
#include <conio.h>
#include <string.h>
int xstrlen ( char * ) ;
void xstrcpy ( char *, char * ) ;
void xstrcat ( char *, char * ) ;
int xstrcmp ( char *, char * ) ;
void show ( char * ) ;
void main( )
{
char s1[ ] = "kicit" ;
char s2[ ] = "Nagpur" ;
char s3[20] ;
int len ;
clrscr( ) ;
printf ( "\nString s1: %s", s1 ) ;
len = xstrlen ( s1 ) ;
printf ( "\nlength of the string s1: %d", len ) ;
printf ( "\nString s2: %s", s2 ) ;
xstrcpy ( s3, s1 ) ;
printf ( "\nString s3 after copying s1 to it: %s", s3 ) ;
xstrcat ( s3, s2 ) ;
printf ( "\nString s3 after concatenation: %s", s3 ) ;
if ( xstrcmp ( s1, s2 ) == 0 )
printf ( "\nThe strings s1 and s2 are similar" ) ;
else
printf ( "\nThe strings s1 and s2 are not similar" ) ;
getch( ) ;
}
/* finds the length of the string */
int xstrlen ( char *s )
{
int l = 0 ;
while ( *s )
{
l++ ;
s++ ;
}
return l ;
}
/* copies source string s to the target string t */
void xstrcpy ( char *t, char *s )
{
while ( *s )
{
*t = *s ;
t++ ;
s++ ;
}
*t = '\0' ;
}
/* concatenates the two strings */
void xstrcat ( char *t, char *s )
{
while ( *t )
t++ ;
while ( *s )
*t++ = *s++ ;
*t = '\0' ;
}
/* compares two strings s and t for equality */
int xstrcmp ( char *s, char *t )
{
while ( *s == *t )
{
if ( ! ( *s ) )
return 0 ;
s++ ;
t++ ;
}
return ( *s - *t ) ;
}