C Standard Library

C <math.h> - nearbyint() Function

The C <math.h> nearbyint() function returns an integral value by rounding up the specified number, using the rounding direction specified by fegetround.

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

Syntax

double nearbyint  (double x);
float nearbyintf (float x);
long double nearbyintl (long double 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, nearbyint() function is used to round the given number.

#include <stdio.h>
#include <fenv.h>
#include <math.h>

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

int main (){
  Rounding_Direction_Message();

  printf("nearbyint(10.2): %.1f\n", nearbyint(10.2));
  printf("nearbyint(10.8): %.1f\n", nearbyint(10.8));
  printf("nearbyint(-5.2): %.1f\n", nearbyint(-5.2));
  printf("nearbyint(-5.8): %.1f\n", nearbyint(-5.8));

  return 0;
}

The output of the above code will be:

Rounding using to-nearest method:
nearbyint(10.2): 10.0
nearbyint(10.8): 11.0
nearbyint(-5.2): -5.0
nearbyint(-5.8): -6.0

❮ C <math.h> Library