Factorial case 13 and 16

[aitía]

My factorial program does not give me the correct results in cases, for instance 13 should be 6227020800 and my output is 1932053504. I display my C program below, is someone able to help me fix it for these cases? I know the formula for factorial is n × (n - 1).

int    factorial(int nb)
{
    int    res;
    int i;

    res = 1;
    i = 1;
    if (nb == 0 || nb == 1)
        return (1);
    while (++i <= nb)
    {
        res *= i;
    }
    return (res);
}

 

[AngleWyrm]

The problem is you're overflowing the maximum value an int can hold. Use a storage variable that can hold a larger quantity, such as double.