#include <stdio.h>
#include <stdlib.h>

long long factorielle(int n) {
    if (n < 0) return -1;
    long long res = 1;
    for (int i = 2; i <= n; i++) {
        res *= i;
    }
    return res;
}

int main() {
    struct {
        int n;
        long long attendu;
    } tests[] = {
        {0, 1},
        {1, 1},
        {2, 2},
        {3, 6},
        {5, 120},
        {10, 3628800},
        {12, 479001600},
        {20, 2432902008176640000LL},
    };
    int nb_tests = sizeof(tests) / sizeof(tests[0]);
    int passes = 0, echoues = 0;

    for (int i = 0; i < nb_tests; i++) {
        long long res = factorielle(tests[i].n);
        if (res == tests[i].attendu) {
            printf("OK   factorielle(%d) = %lld\n", tests[i].n, res);
            passes++;
        } else {
            printf("FAIL factorielle(%d) = %lld (attendu %lld)\n",
                   tests[i].n, res, tests[i].attendu);
            echoues++;
        }
    }

    printf("\n%d passes, %d echoues sur %d tests\n", passes, echoues, nb_tests);
    return echoues > 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}