# C++ cmath abs()

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

The abs function is identical to fabs() in C++.

The function is defined in <cmath> header file.

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

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

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

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

## abs() Parameters

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

## abs() Return value

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

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

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

using namespace std;

int main()
{
double x = -87.91, result;

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

return 0;
}```
```

When you run the program, the output will be:

```abs(-87.91) = |-87.91| = 87.91
```

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

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

using namespace std;

int main()
{
long int x = -101;
double result;

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

return 0;
}```
```

When you run the program, the output will be:

```abs(-101) = |-101| = 101
```