This C program accepts two strings as input and checks if the second string is a substring of the first string. If it is a substring, the program outputs the starting and ending locations of each occurrence of the substring in the main string. If the substring is not found, the program outputs "Not substring". It uses a while loop to iterate through the strings and compare characters to find substring matches and their positions.

1. S1-3
Write a program in `C’ Language that accepts two strings S1 and S2 as input. The
program should check
if S2 is a substring of S1 or not. If S2 is a substring of S1, then the program
should output the
starting location and ending location of S2 in S1. If S2 appears more than once
in S1, then the
locations of all instances have to be given.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
int i=0,j=0,v,c=0,l1,l2;
char s1[50],s2[50];
clrscr();
printf("Enter 2 strings:n");
gets(s1);
gets(s2);
l1=strlen(s1);
l2=strlen(s2);
while(i<=l1)
{
if(j==l2)
{
v=i-l2+1;
c++;
printf("Start of %d occurance=%d end =%dn",c,v,i);
j=0;
}
else if(s1[i]==s2[j])
{
i++;
j++;
}
else
{
i++;
j=0;
}
}
if(c==0)
printf("Not substring");
getch();
}
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