cbrt, cbrtf, cbrtl
Defined in header <math.h>
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(1) | (since C99) |
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(2) | (since C99) |
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(3) | (since C99) |
Defined in header <tgmath.h>
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(4) | (since C99) |
1-3) Computes the cubic root of arg
.
4) Type-generic macro: If arg
has type long double
, cbrtl
is called. Otherwise, if arg
has integer type or the type double
, cbrt
is called. Otherwise, cbrtf
is called.
Parameters
arg | - | floating point value |
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
cbrt(arg)
is not equivalent to pow(arg, 1.0/3)
because pow
cannot raise a negative base to a fractional exponent.
Example
#include <stdio.h>
#include <math.h>
int main(void)
{
// normal use
printf("cbrt(729) = %f\n", cbrt(729));
printf("cbrt(-0.125) = %f\n", cbrt(-0.125));
// special values
printf("cbrt(-0) = %f\n", cbrt(-0.0));
printf("cbrt(+inf) = %f\n", cbrt(INFINITY));
}
Output:
cbrt(729) = 9.000000
cbrt(-0.125) = -0.500000
cbrt(-0) = -0.000000
cbrt(+inf) = inf
References
C11 standard (ISO/IEC 9899:2011):
- 7.12.7.1 The cbrt functions (p: 247)
- 7.25 Type-generic math (p: 373-375)
- F.10.4.1 The cbrt functions (p: 524)
C99 standard (ISO/IEC 9899:1999):
- 7.12.7.1 The cbrt functions (p: 228)
- 7.22 Type-generic math (p: 335-337)
- F.9.4.1 The cbrt functions (p: 460)
See also
(C99)(C99) |
computes a number raised to the given power (xy) (function) |
(C99)(C99) |
computes square root (√x) (function) |
(C99)(C99)(C99) |
computes square root of the sum of the squares of two given numbers (√x2+y2) (function) |
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