roundeven, roundevenf, roundevenl
From cppreference.com
Defined in header <math.h>
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float roundevenf( float arg ); |
(1) | (since C23) |
double roundeven( double arg ); |
(2) | (since C23) |
long double roundevenl( long double arg ); |
(3) | (since C23) |
Defined in header <tgmath.h>
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#define roundeven( arg ) |
(4) | (since C23) |
1-3) Computes the nearest integer value to arg (in floating-point format), rounding halfway cases to nearest even integer, regardless of the current rounding mode.
4) Type-generic macro: If arg has type long double,
roundevenl
is called. Otherwise, if arg has integer type or the type double, roundeven
is called. Otherwise, roundevenf
is called, respectively.Contents |
[edit] Parameters
arg | - | floating-point value |
[edit] Return value
If no errors occur, the nearest integer value to arg, rounding halfway cases to nearest even integer, is returned.
[edit] Error handling
This function is not subject to any of the errors specified in math_errhandling
.
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
- FE_INEXACT is never raised.
- If arg is ±∞, it is returned, unmodified.
- If arg is ±0, it is returned, unmodified.
- If arg is NaN, NaN is returned.
[edit] Example
Run this code
#include <math.h> #include <stdio.h> int main(void) { printf("roundeven(+2.4) = %+.1f\n", roundeven(2.4)); printf("roundeven(-2.4) = %+.1f\n", roundeven(-2.4)); printf("roundeven(+2.5) = %+.1f\n", roundeven(2.5)); printf("roundeven(-2.5) = %+.1f\n", roundeven(-2.5)); printf("roundeven(+2.6) = %+.1f\n", roundeven(2.6)); printf("roundeven(-2.6) = %+.1f\n", roundeven(-2.6)); printf("roundeven(+3.5) = %+.1f\n", roundeven(3.5)); printf("roundeven(-3.5) = %+.1f\n", roundeven(-3.5)); printf("roundeven(-0.0) = %+.1f\n", roundeven(-0.0)); printf("roundeven(-Inf) = %+f\n", roundeven(-INFINITY)); }
Possible output:
roundeven(+2.4) = +2.0 roundeven(-2.4) = -2.0 roundeven(+2.5) = +2.0 roundeven(-2.5) = -2.0 roundeven(+2.6) = +3.0 roundeven(-2.6) = -3.0 roundeven(+3.5) = +4.0 roundeven(-3.5) = -4.0 roundeven(-0.0) = -0.0 roundeven(-Inf) = -inf
[edit] References
- C23 standard (ISO/IEC 9899:2024):
- 7.12.9.8 The roundeven functions (p: 265-266)
- 7.27 Type-generic math <tgmath.h> (p: 386-390)
- F.10.6.8 The roundeven functions (p: 532)
[edit] See also
(C99)(C99)(C99)(C99)(C99)(C99)(C99)(C99)(C99) |
rounds to an integer using current rounding mode with exception if the result differs (function) |
(C99)(C99)(C99)(C99)(C99)(C99)(C99)(C99)(C99) |
rounds to nearest integer, rounding away from zero in halfway cases (function) |