#include <string.h>

int strncmp(const char *s1, const char *s2, size_t n)
{
    for (size_t i = 0; i < n; i++)
    {
        char c1 = s1[i], c2 = s2[i];
        if (c1 != c2)
            return c1 - c2;
        if (!c1)
            return 0;
    }
    return 0;
}