fmax() and fmin() in C++

fmax() and fmin() functions are defined in cmath header file.

1. fmax() function: The syntax of this function is:

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

1. The input to this function are two values of type float, double or long double. The function returns maximum of the two input values. Below is sample C++ program to show working of fmax() function: 

CPP

// CPP program to show working
// of fmax() function.

#include <cmath>
#include <iomanip>
#include <iostream>

using namespace std;

int main()
{
    double val;

    // Find maximum value when both the inputs
    // are positive.
    val = fmax(10.0, 1.0);
    cout << fixed << setprecision(4)
        << "fmax(10.0, 1.0) = " << val << "\n";

    // Find maximum value when inputs have
    // opposite sign.
    val = fmax(-10.0, 1.0);
    cout << fixed << setprecision(4)
        << "fmax(-10.0, 1.0) = " << val << "\n";

    // Find maximum value when both the inputs
    // are negative.
    val = fmax(-10.0, -1.0);
    cout << fixed << setprecision(4)
        << "fmax(-10.0, -1.0) = " << val << "\n";

    return 0;
}

Output:

fmax(10.0, 1.0) = 10.0000
fmax(-10.0, 1.0) = 1.0000
fmax(-10.0, -1.0) = -1.0000

Time Complexity: O(1)

Space Complexity: O(1)

1. fmin() function: The syntax of this function is:

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

1. The input to this function are two values of type float, double or long double. The function returns minimum of the two input values. Below is sample C++ program to show working of fmin() function: 

CPP

// CPP program to show working
// of fmin() function.

#include <cmath>
#include <iomanip>
#include <iostream>

using namespace std;

int main()
{
    double val;

    // Find minimum value when both the inputs
    // are positive.
    val = fmin(10.0, 1.0);
    cout << fixed << setprecision(4)
        << "fmin(10.0, 1.0) = " << val << "\n";

    // Find minimum value when inputs have
    // opposite sign.
    val = fmin(-10.0, 1.0);
    cout << fixed << setprecision(4)
        << "fmin(-10.0, 1.0) = " << val << "\n";

    // Find minimum value when both the inputs
    // are negative.
    val = fmin(-10.0, -1.0);
    cout << fixed << setprecision(4)
        << "fmin(-10.0, -1.0) = " << val << "\n";

    return 0;
}

Output:

fmin(10.0, 1.0) = 1.0000
fmin(-10.0, 1.0) = -10.0000
fmin(-10.0, -1.0) = -10.0000

Time Complexity: O(1)

Space Complexity: O(1)

Note : Consider a case when the arguments of the function are of different types. In that case, the arguments are first implicity typecast by the function and then the required maximum/minimum value is returned.
Below is sample C++ program that illustrates this case:

C++

// CPP program to show working
// of fmin() and fmax()function
// when input values are of
// different data types.

#include <cmath>
#include <iomanip>
#include <iostream>

using namespace std;

int main()
{
    double val;

    // Find minimum value when one of the inputs
    // is of type float and other is of type
    // double.
    val = fmin(10.0f, 1.0);
    cout << fixed << setprecision(4)
        << "fmin(10.0f, 1.0) = " << val << "\n";

    // Find maximum value when one of the inputs
    // is of type float and other is of type
    // double.
    val = fmax(10.0, -1.0f);
    cout << fixed << setprecision(4)
        << "fmax(10.0, -1.0f) = " << val << "\n";

    return 0;
}

Output

fmin(10.0f, 1.0) = 1.0000
fmax(10.0, -1.0f) = 10.0000

Time Complexity: O(1)

Space Complexity: O(1)