Ceil function: how can we implement it ourselves?

Question

I know that C++ provides us with a ceil function. For practice, I was wondering how can we implement the ceil function in C++. The signature of the method is public static

Answer 1

Here's one that works with negative numbers:

int ceil(float num) {
    int inum = (int)num;
    if (num < 0 || num == (float)inum) {
        return inum;
    }
    return inum + 1;
}