Concatenate Two Strings

You can concatenate two strings easily using standard library function strcat() but, this program concatenates two strings manually without using strcat() function.

Source Code to Concatenate Two Strings Manually

#include <stdio.h>
int main()
{
    char s1[100], s2[100], i, j;
    printf("Enter first string: ");
    scanf("%s",s1);
    printf("Enter second string: ");
    scanf("%s",s2);
    for(i=0; s1[i]!='\0'; ++i);  /* i contains length of string s1. */
    for(j=0; s2[j]!='\0'; ++j, ++i)
    {
        s1[i]=s2[j];
    }
    s1[i]='\0';
    printf("After concatenation: %s",s1);
    return 0;
}

Output

Enter first string: lol
Enter second string: :)
After concatenation: lol:)