cbrt, cbrtf, cbrtl

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< c‎ | numeric‎ | math
 
 
 
Common mathematical functions
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(C99)(C99)(C99)
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cbrt
(C99)
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Macro constants
 
Defined in header <math.h>
float       cbrtf( float arg );
(1) (since C99)
double      cbrt( double arg );
(2) (since C99)
long double cbrtl( long double arg );
(3) (since C99)
Defined in header <tgmath.h>
#define cbrt( arg )
(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.

Contents

[edit] Parameters

arg - floating point value

[edit] Return value

If no errors occur, the cubic root of arg (3arg), 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

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

[edit] Example

#include <stdio.h>
#include <math.h>
 
int main()
{
    // 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

[edit] 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)