C++ cmath cbrt() Function

The C++ cmath cbrt() function computes the cube root of a number. This means it finds a value that, when multiplied by itself two more times (or raised to the power of three), gives the original number. The function works with positive numbers, negative numbers, and zero.

The function accepts various numeric types such as double, float, and long double. It's especially useful for quickly calculating the cube root of decimal numbers without needing to use more complex calculations.

Syntax

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

double cbrt(double x);
or
float cbrt(float x);
or
long double cbrt(long double x);

Parameters

• x - The value whose cubic root is computed.

Return Value

The function returns the cube root of the given number.

Time Complexity

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

Example 1

In this example, the function cbrt() is used to find the cube root of a positive number.

#include <iostream>
#include <cmath>
int main() {
   double number = 27.0;
   double result = std::cbrt(number);
   std::cout << "Cube root of " << number << " is: " << result << std::endl;
   return 0;
}

Output

The output of the above code is as follows

Cube root of 27 is: 3

Example 2

In this example, the function cbrt() is used to calculate the cube root of a fraction.

#include <iostream>
#include <cmath>
int main() {
   double value = 0.125;
   double result = cbrt(value);
   std::cout << "The cube root of " << value << " is " << result << std::endl;
   return 0;
}

Output

Following is the output of the above code

The cube root of 0.125 is 0.5

Example 3

The example demonstrates how the cbrt() function effectively calculates the cube root of a very large number, highlighting its ability to manage complex calculations with large values accurately.

#include <iostream>
#include <cmath>
int main() {
   double value = 1e12; 
   double result = cbrt(value);
   std::cout << "The cube root of " << value << " is " << result << std::endl;
   return 0;
}

Output

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

The cube root of 1e+12 is 10000