# C++ fabs()

The fabs() function in C++ returns the absolute value of the argument.

It is defined in <cmath> header file.

`[Mathematics] |x| = fabs(x) [C++ Programming]`

## fabs() prototype [As of C++ 11 standard]

```double fabs(double x);
float fabs(float x);
long double fabs(long double x);
double fabs(T x); // For integral type```

The fabs() function takes a single argument and returns a value of type `double`, `float` or `long double` type.

## fabs() Parameters

The fabs() function takes a single argument, x whose absolute value is returned.

## fabs() Return value

The fabs() function returns the absolute value of x i.e. |x|.

## Example 1: How fabs() function works in C++?

``````#include <iostream>
#include <cmath>

using namespace std;

int main()
{
double x = -10.25, result;

result = fabs(x);
cout << "fabs(" << x << ") = |" << x << "| = " << result << endl;

return 0;
}```
```

When you run the program, the output will be:

```fabs(-10.25) = |-10.25| = 10.25
```

## Example 2: fabs() function for integral types

``````#include <iostream>
#include <cmath>

using namespace std;

int main()
{
long int x = -23;
double result;

result = fabs(x);
cout << "fabs(" << x << ") = |" << x << "| = " << result << endl;

return 0;
}```
```

When you run the program, the output will be:

```fabs(-23) = |-23| = 23
```