FloorMod for Go

FloorMod.go

// For modulo not remainder: 
// n mod m = n-⌊nm⌋.m
func FloorMod(n, m int) int {
    res := n % m // remainder operator, strictly speaking: example- 
    //If -8 % 7 == 6, you're fine, but if it is -1, you'll need to adjust it by 
    //adding m to any negative results as below.
    if res < 0 {
        res += m
    }
    return res
}