long long int llround(double x); long long int llround(float x); long long int llround(long double x); long long int llround(T x); //為整型
llround()函數(shù)采用單個參數(shù)，并返回long long int類型的值。此函數(shù)在<cmath>頭文件中定義。
llround()函數(shù)將單個參數(shù)值取整。
llround()函數(shù)返回最接近x的整數(shù)值，中間情況下從零舍入。返回的值是long long int類型。
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
long long int result;
double x = 11.16;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
x = 13.87;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
x = 50.5;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
x = -11.16;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
x = -13.87;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
x = -50.5;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
return 0;
}運行該程序時，輸出為：
llround(11.16) = 11 llround(13.87) = 14 llround(50.5) = 51 llround(-11.16) = -11 llround(-13.87) = -14 llround(-50.5) = -51
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int x = 15;
long long int result;
result = llround(x);
cout << "llround(" << x << ") = " << result << endl;
return 0;
}運行該程序時，輸出為：
llround(15) = 15
對于整數(shù)值，應用llround函數(shù)將返回與輸入相同的值。所以它在實際中并不常用來表示整數(shù)值。