In this C++ tutorial, you will learn how to find the positive different between two given numbers using fdim() function of cmath, with syntax and examples.

C++ fdim()

C++ fdim(x, y) returns positive different between x and y.

fdim() returns x-y if x>=0, else it returns 0.

Syntax

The syntax of C++ fdim() is

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fdim(x, y)

where

ParameterDescription
xA double, float, long double, or integral type value.
yA double, float, long double, or integral type value.

Returns

The return value depends on the type of value passed for parameters x and y. The return value of fdim() is

  • double if x and y are double.
  • float if x and y are float.
  • long double if x and y are long double.
  • Promoted to the higher of the given arguments for integral type arguments.

The synopsis of fdim() function is

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double fdim(double x, double y);
float fdim(float x, float y);
long double fdim(long double x, long double y);
Promoted fdim(Type1 x, Type2 y); // for integral type argument values

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

Example

In this example, we read two values from user into x and y, and find the positive difference of x and y using fdim(x, y) function.

C++ Program

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

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

    double result = fdim(x, y);
    cout << "fdim(x, y) : " << result << endl;
}

Output

Enter x : 24
Enter y : 15
fdim(x, y) : 9
Program ended with exit code: 0

Since x-y is greater than 0, fdim(x, y) returns the difference of x and y.

Run#2

Enter x : 23
Enter y : 68
fdim(x, y) : 0
Program ended with exit code: 0

Since x-y is greater than 0, fdim(x, y) returns 0.

Conclusion

In this C++ Tutorial, we learned the syntax of C++ fdim(), and how to use this function to find the positive difference, with the help of examples.