String Concatination

#include <stdio.h>

void stringConcat(char str1[], char str2[]);

int main()
{
    char s1[] = "BUET";
    char s2[100] = "Programming";

    stringConcat(s1, s2);

    printf(s2);

    return 0;
}

void stringConcat(char str1[], char str2[])
{
    int i, j;

    for(i = 0; str2[i] != '\0'; i++)
        ;
    for(j = 0; str1[j] != '\0'; i++, j++)
        str2[i] = str1[j];
    str2[i] = '\0';
}