What is the fmax() function in C++?

Overview

The fmax() function in C++ is used to return the larger number among two arguments (x and y) passed to the function.

The fmax() function is defined in the <cmath> header file.

Syntax

double fmax (double x, double y);
float fmax (float x, float y);
long double fmax (long double x, long double y);

Parameter value

The fmax() function takes two parameter values, x and y, which represent the first and second arguments of the function, respectively.

Return value

The fmax() function returns the larger value among the x and y values.

Example

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    double x = -2.05, y = -3.5, result;
    result = fmax(x, y);
    cout << "fmax(x, y) = " << result << endl;
    return 0;
}

Code explanation

We can see from the code above that the fmax() function correctly returned -2.05 as the larger value when compared to -3.5.

Using different types of argument

We can also use the fmax() function to compute for the larger number between arguments of different data types, such as a double and an int.

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
  // using different argument types
    double x = 89.1, result;
    int y = 89;
    
    result = fmax(x, y);
    cout << "fmax(89.1, 89) = " << result << endl;
    return 0;
}

Code explanation

We can see from the code above that the fmax() correctly returned the double (89.1) as the larger value when compared to the int (89).

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