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std::cbrt, std::cbrtf, std::cbrtl

Defined in header `<cmath>`
float cbrt ( float arg ); float cbrtf( float arg );	(1)	(since C++11)
double cbrt ( double arg );	(2)	(since C++11)
long double cbrt ( long double arg ); long double cbrtl( long double arg );	(3)	(since C++11)
double cbrt ( IntegralType arg );	(4)	(since C++11)

1-3) Computes the cubic root of arg.

4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to 2) (the argument is cast to double).

Parameters

arg

value of a floating-point or Integral type

Return value

If no errors occur, the cubic root of arg (3√arg), is returned.

If a range error occurs due to underflow, the correct result (after rounding) is returned.

Error handling

Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

if the argument is ±0 or ±∞, it is returned, unchanged
if the argument is NaN, NaN is returned.

Notes

std::cbrt(arg) is not equivalent to std::pow(arg, 1.0/3) because std::pow cannot raise a negative base to a fractional exponent.

Example

#include <iostream>
#include <cmath>
 
int main()
{
    // normal use
    std::cout << "cbrt(729) = " << std::cbrt(729) << '\n'
              << "cbrt(-0.125) = " << std::cbrt(-0.125) << '\n';
    // special values
    std::cout << "cbrt(-0) = " << std::cbrt(-0.0) << '\n'
              << "cbrt(+inf) = " << std::cbrt(INFINITY) << '\n';
}

Output:

cbrt(729) = 9
cbrt(-0.125) = -0.5
cbrt(-0) = -0
cbrt(+inf) = inf