In this C++ tutorial, you will learn how to round given number to nearest integral value using nearbyint() function of cmath, with syntax and examples.

## C++ nearbyint()

C++ nearbyint(x) rounds argument x to nearest integral value, using current rounding mode.

The current rounding mode can be accessed using fesetround() and fegetround().

## Syntax

The syntax of C++ nearbyint() is

`nearbyint(x)`

where

Returns

The return value depends on the type of value passed for parameter x.

The return value of nearbyint(x) is

• double if x is double or integral type.
• float if x is float.
• long double if x is long double.

The synopsis of nearbyint() function is

```double sinh(double x);
float sinh(float x);
long double sinh(long double x);
double sinh(T x); // for integral type argument values```

nearbyint() is a function of cmath library. Include cmath library at the start of program, if using nearbyint() function.

## Example

In this example, we read a value from user into variable x, and find the nearest integral value of x using nearbyint() function.

C++ Program

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

int main() {
double x;
cout << "Enter x   : ";
cin >> x;

double result = nearbyint(x);
cout << "nearbyint(" << x << ") : " << result << endl;
}```

Output

```Enter x   : 5.23
nearbyint(5.23) : 5
Program ended with exit code: 0```
```Enter x   : 9.89
nearbyint(9.89) : 10
Program ended with exit code: 0```
```Enter x   : nan
nearbyint(nan) : nan
Program ended with exit code: 0```

## Conclusion

In this C++ Tutorial, we learned the syntax of C++ nearbyint(), and how to use this function to find the nearest integral value, with the help of examples.