C++ 取整函数

#include  <bits/stdc++.h>

using namespace std;

const int N = 110;

signed main()
{
    cout << ceil(1.0 * 9 / 2) << endl;     //向上取整
    cout << floor(1.0 * 9 / 2) << endl;    //向下取整
    cout << round(1.0 * 5 / 10) << endl;   //四舍五入
    cout << round(1.0 * 4 / 10) << endl;
    /*
    5
    4
    1
    0
    */
    return 0;
}