//concatenate two string with out using strcat() function //
#include <stdio.h>
int main()
{
    char str1[50], str2[50], i, j;
    printf("Enter first string: ");
    gets(str1);
    printf("Enter second string: ");
    gets(str2);

    for(i = 0; str1[i] != '\0'; ++i);
    for(j = 0; str2[j] != '\0'; ++j, ++i)
    {
        str1[i] =  str2[j];
    }
    str1[i] = '\0';
    printf(" %s", str1);
    return 0;
}