std::cbrt, std::cbrtf, std::cbrtl
From cppreference.com
| Defined in header <cmath>
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| (1) | ||
float cbrt ( float num ); double cbrt ( double num ); |
(until C++23) | |
| /*floating-point-type*/ cbrt ( /*floating-point-type*/ num ); |
(since C++23) (constexpr since C++26) |
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float cbrtf( float num ); |
(2) | (since C++11) (constexpr since C++26) |
long double cbrtl( long double num ); |
(3) | (since C++11) (constexpr since C++26) |
| SIMD overload (since C++26) |
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| Defined in header <simd>
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| template< /*math-floating-point*/ V > constexpr /*deduced-simd-t*/<V> |
(S) | (since C++26) |
| Additional overloads (since C++11) |
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| Defined in header <cmath>
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template< class Integer > double cbrt ( Integer num ); |
(A) | (constexpr since C++26) |
1-3) Computes the cube root of num. The library provides overloads of
std::cbrt for all cv-unqualified floating-point types as the type of the parameter.(since C++23)|
S) The SIMD overload performs an element-wise
std::cbrt on v_num.
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(since C++26) |
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A) Additional overloads are provided for all integer types, which are treated as double.
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(since C++11) |
Contents |
[edit] Parameters
| num | - | floating-point or integer value |
[edit] Return value
If no errors occur, the cube root of num (3√num), is returned.
If a range error occurs due to underflow, the correct result (after rounding) is returned.
[edit] 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.
[edit] Notes
std::cbrt(num) is not equivalent to std::pow(num, 1.0 / 3) because the rational number| 1 |
| 3 |
The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their argument num of integer type, std::cbrt(num) has the same effect as std::cbrt(static_cast<double>(num)).
[edit] Example
Run this code
#include <cmath> #include <iomanip> #include <iostream> #include <limits> int main() { std::cout << "Normal use:\n" << "cbrt(729) = " << std::cbrt(729) << '\n' << "cbrt(-0.125) = " << std::cbrt(-0.125) << '\n' << "Special values:\n" << "cbrt(-0) = " << std::cbrt(-0.0) << '\n' << "cbrt(+inf) = " << std::cbrt(INFINITY) << '\n' << "Accuracy and comparison with `pow`:\n" << std::setprecision(std::numeric_limits<double>::max_digits10) << "cbrt(343) = " << std::cbrt(343) << '\n' << "pow(343,1.0/3) = " << std::pow(343, 1.0 / 3) << '\n' << "cbrt(-343) = " << std::cbrt(-343) << '\n' << "pow(-343,1.0/3) = " << std::pow(-343, 1.0 / 3) << '\n'; }
Possible output:
Normal use: cbrt(729) = 9 cbrt(-0.125) = -0.5 Special values: cbrt(-0) = -0 cbrt(+inf) = inf Accuracy and comparison with `pow`: cbrt(343) = 7 pow(343,1.0/3) = 6.9999999999999991 cbrt(-343) = -7 pow(-343,1.0/3) = -nan
[edit] See also
| (C++11)(C++11) |
raises a number to the given power (xy) (function) |
| (C++11)(C++11) |
computes square root (√x) (function) |
| (C++11)(C++11)(C++11) |
computes hypotenuse √x2 +y2 and √x2 +y2 +z2 (since C++17) (function) |
| C documentation for cbrt
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