c++向上取整和向下取整

#include <map>  
#include <string>  
#include <iostream>  
#include <cmath>
using namespace std;
 
 
int main()
{
    cout << floor(2.4) << endl;//2
    cout << floor(2.7) << endl;//2
    cout << ceil(2.4) << endl;//3
    cout << ceil(2.7) << endl;//3
    cout << round(2.4) << endl;//2
    cout << round(2.7) << endl;//3
    return 0;
}