C++ Standard Library C++ STL Library

C++ <cmath> - rint() Function



The C++ <cmath> rint() function returns an integral value by rounding up the specified number, using the rounding direction specified by fegetround.

This function may raise FE_INEXACT exceptions, if the returned value differs from x. The nearbyint() function is similar to this function, except it do not raise FE_INEXACT exceptions.

Syntax

double rint (double x);
float rint (float x);
long double rint (long double x);
double rint (T x);                        

Parameters

x Specify a value to round.

Return Value

Returns an integral value by rounding up the x, using the rounding direction specified by fegetround.

Example:

In the example below, rint() function is used to round the given number.

#include <iostream>
#include <cfenv>
#include <cmath>
using namespace std;

void Rounding_Direction_Message(void) {
  cout<<"Rounding using ";
  switch(fegetround()) {
    case FE_DOWNWARD: 
      cout<<"downward"; break;
    case FE_TONEAREST:   
      cout<<"to-nearest"; break;
    case FE_TOWARDZERO:   
      cout<<"toward-zero"; break;
    case FE_UPWARD:  
      cout<<"upward"; break;
    default:
      cout<<"unknown";
  }
  cout<<" method:"<<endl;
}

int main (){
  Rounding_Direction_Message();

  cout<<"rint(10.2): "<<rint(10.2)<<"\n";
  cout<<"rint(10.8): "<<rint(10.8)<<"\n";
  cout<<"rint(-5.2): "<<rint(-5.2)<<"\n";
  cout<<"rint(-5.8): "<<rint(-5.8)<<"\n";

  return 0;
}

The output of the above code will be:

Rounding using to-nearest method:
rint(10.2): 10
rint(10.8): 11
rint(-5.2): -5
rint(-5.8): -6

❮ C++ <cmath> Library

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