C ++中的round()函數(shù)返回最接近參數(shù)的整數(shù)值，在中間的情況從零舍入。
double round(double x); float round(float x); long double round(long double x); double round(T x); // 為整型
round()函數(shù)采用單個參數(shù)，并返回double，float或long double類型的值。此函數(shù)在<cmath>頭文件中定義。
round()函數(shù)采用單個參數(shù)值進(jìn)行舍入。
round()函數(shù)返回最接近x的整數(shù)值，在中間情況下從零舍入。
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double x = 11.16, result;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
x = 13.87;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
x = 50.5;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
x = -11.16;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
x = -13.87;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
x = -50.5;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
return 0;
}運(yùn)行該程序時，輸出為：
round(11.16) = 11 round(13.87) = 14 round(50.5) = 51 round(-11.16) = -11 round(-13.87) = -14 round(-50.5) = -51
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int x = 15;
double result;
result = round(x);
cout << "round(" << x << ") = " << result << endl;
return 0;
}運(yùn)行該程序時，輸出為：
round(15) = 15
對于整數(shù)值，應(yīng)用round函數(shù)將返回與輸入相同的值。所以它在實(shí)際中并不常用來表示整數(shù)值。