Built-in mod ('%') vs custom mod function: improve the performance of modulus operation

Question

Recently I came to know that the mod(\'%\') operator is very slow. So I made a function which will work just like a%b. But is it faster than the mod operator?

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Answer 1

Just contributing a little bit with this discussion. If you want to handle negative numbers, use the following function:

inline long long mod(const long long x, const long long y) {
    if (x >= y) {
        return x % y;
    } else if (x < 0) {
        return (x % y + y) % y;
    } else {
        return x;
    }
}