In this C++ tutorial, you will learn how to compute cube root of a given number using cbrt() function of cmath, with syntax and examples.

C++ cbrt()

C++ cbrt() computes cube root of given number (argument).


The syntax of C++ cbrt() is



xA double, float, long double, or any integral type value.


The return value depends on the type of value passed for parameter x.

The return value of cbrt(x) is

  • double if x is double or integral type.
  • float if x is float.
  • long double if x is long double.

The synopsis of cbrt() function is

double cbrt(double x);
float cbrt(float x);
long double cbrt(long double x);
double cbrt(T x); // for integral type argument values

cbrt() is a function of cmath library. Include cmath library at the start of program, if using cbrt() function.



In this example, we read a value from user into variable x, and find its cube root using cbrt() function.

C++ Program

#include <iostream>
using namespace std;

int main() {
    double x;
    cout << "Enter a number : ";
    cin >> x;
    double result = cbrt(x);
    cout << "cbrt(" << x << ") : " << result << endl;


Enter a number : 27
cbrt(27) : 3
Program ended with exit code: 0
Enter a number : -27
cbrt(-27) : -3
Program ended with exit code: 0


In this C++ Tutorial, we learned the syntax of C++ cbrt(), and how to use this function to find the cube root of given number, with the help of examples.