C++ cmath abs() Function

The C++ cmath abs() function calculates the absolute value of a number, which means it returns the number without its sign, making it non-negative. It works with different data types, such as integers (int), floating-point numbers (float), and double-precision numbers (double). This function is helpful in mathematical calculations where you need the positive value of a number.

Syntax

Following is the syntax for C++ cmath abs() function.

int abs(int x);
or
float abs(float x);
or
double abs(double x);
or
long double abs(long double x);

Parameters

• x - The value whose absolute value is to be computed.

Return Value

The function returns the absolute value of the given number.

Time Complexity

The time complexity of this function is constant, i.e.,O(1).

Example 1

In the following example, a negative integer was passed to abs() function it returns the absolute value, by eliminating the negative sign.

#include <iostream>
#include <cmath>
int main() {
   int num = -10;
   std::cout << "Absolute value of " << num << " is: " << std::abs(num) << std::endl;
   return 0;
}

Output

Output of the above code is as follows

Absolute value of -10 is: 10

Example 2

This example shows that abs() can also be used with floating-point numbers. It computes the absolute value of negative float number.

#include <iostream>
#include <cmath>
int main() {
   double x = -3.14;
   double result = abs(x);
   std::cout << "abs(-3.14) = " << result << std::endl;
   return 0;
}

Output

If we run the above code it will generate the following output

abs(-3.14) = 3

Example 3

This example illustrates the use of std::abs() with a double input to showcase its functionality with higher precision values.

#include <iostream>
#include <cmath>
int main() {
   double num = -123.456789;
   std::cout << "Absolute value of " << num << " is: " << std::abs(num) << std::endl;
   return 0;
}

Output

Following is the output of the above code

Absolute value of -123.457 is: 123.457