strcmp in c meaning code example

Example 1: strcmp in c

#include 
#include 

int main()
{
    char str1[] = "abcd", str2[] = "abCd", str3[] = "abcd";
    int result;

    // comparing strings str1 and str2
    result = strcmp(str1, str2);
    printf("strcmp(str1, str2) = %d\n", result);

    // comparing strings str1 and str3
    result = strcmp(str1, str3);
    printf("strcmp(str1, str3) = %d\n", result);

    return 0;
}

Example 2: c strcmp

// strCmp implementation
// string1 < string2 => return a negative integer
// string1 > string2 => return a positive integer
// string1 = string2 => return 0
int strCmp(const char* s1, const char* s2) {
    while(*s1 && (*s1 == *s2)) {
        s1++;
        s2++;
    }
    return *s1 - *s2;
}