C++ Math lrint()

The function rounds off the given value using current rounding mode and returns the value of type long int.

Syntax

Suppose a number is 'x'. Syntax would be:

Parameter

x: The value that can be float, double or long double.

Return value

It returns the rounded value of x and the return type of the value is long int.

Example 1

Let's see a simple example.

#include <iostream>
#include<math.h>
#include <cfenv>
using namespace std;
int main()
{
    float r;
    int str;
    cout<<"Enter the value which you want to round :";
    std::cin >> r ;
    cout<<'\n';
    cout<<"Name of the methods are :"<<'\n'<<"1. Rounding downwards"<<'\n'<<"2. Rounding upwards"<<'\n'<<"3. 
    Rounding towards zero"<<'\n'<<"4. Rounding to the nearest"<<'\n';
    cout<<"Enter the number of rounding method :";
    cin>>str;
    cout<<'\n';
    switch(str)
    {
        case 1:
        fesetround(FE_DOWNWARD);
        cout<<"Rounding downwards,value is :"<<lrint(r)<<'\n';
        break;
        case 2:
        fesetround(FE_UPWARD);
        cout<<"Rounding upwards,value is :"<<lrint(r)<<'\n';
        break;
        case 3:
        fesetround(FE_TOWARDZERO);
        cout<<"Rounding towards zero,value is :"<<lrint(r)<<'\n';
        break;
        case 4:
        fesetround(FE_TONEAREST);
        cout<<"Rounding to nearest,value is :"<<lrint(r)<<'\n';
        break;
        default:
        cout<<"wrong method";
    }
       return 0;
}

Output:

Enter the value which you want to round : 7.8

Name of the methods are :
1. Rounding downwards
2. Rounding upwards
3. Rounding towards zero
4. Rounding to the nearest
Enter the number of rounding method : 1

Rounding downwards,value is :7

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