C++ cmath abs()

The `abs()` function in C++ returns the absolute value of the argument. It is defined in the cmath header file.

Mathematically, `abs(num) = |num|`.

Example

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

int main() {

// get absolute value of -5.5
cout << abs(-5.5);

return 0;
}

// Output: 5.5``````

Syntax of abs()

The syntax of the `abs()` function is:

``abs(double num);``

abs() Parameters

The `abs()` function takes the following parameter:

• num - a floating point number whose absolute value is returned. It can be of the following types:
• `double`
• `float`
• `long double`

abs() Return Value

The `abs()` function returns:

• the absolute value of num i.e. `|num|`

abs() Prototypes

The prototypes of `abs()` as defined in the cmath header file are:

``````double abs(double num);

float abs(float num);

long double abs(long double num);

// for integral types
double abs(T num);``````

Note: The cmath `abs()` function is identical to the fabs() function.

Example 1: C++ abs()

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

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

result = abs(num);

cout << "abs(" << num << ") = |" << num << "| = " << result;

return 0;
}``````

Output

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

Example 2: C++ abs() for Integral Types

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

using namespace std;

int main() {
int num = -101;
double result;

result = abs(num);

cout << "abs(" << num << ") = |" << num << "| = " << result;

return 0;
}``````

Output

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