C++ Round Function

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
    double a;

    a = 5.45;

    cout << "round(" << a << ") = " << round(a) << endl;

    a = 5.57;

    cout << "round(" << a << ") = " << round(a) << endl;

    return 0;
}