c - Implementation of strcmp

Question

I tried to implement strcmp:

int strCmp(char string1[], char string2[])
{
    int i = 0, flag = 0;    
    while (flag == 0) {
        if (string1[i] > string2[i]) {
            flag = 1;
        } else
        if (string1[i] < string2[i]) {
            flag = -1;
        } else {
            i++;
        }
    }
    return flag;
}

but I'm stuck with the case that the user will input the same strings, because the function works with 1 and -1, but it's doesn't return 0. Can anyone help? And please without pointers!

Answer 1

Uhm.. way too complicated. Go for this one:

int strCmp(const char* s1, const char* s2)
{
    while(*s1 && (*s1 == *s2))
    {
        s1++;
        s2++;
    }
    return *(const unsigned char*)s1 - *(const unsigned char*)s2;
}

It returns <0, 0 or >0 as expected

You can't do it without pointers. In C, indexing an array is using pointers.

Maybe you want to avoid using the * operator? :-)