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

fdim(x, y)

where

Parameter Description
x A double, float, long double, or integral type value.
y A 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

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

#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.