FE_DOWNWARD, FE_TONEAREST, FE_TOWARDZERO, FE_UPWARD
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| Definido en el archivo de encabezado <cfenv>
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| #define FE_DOWNWARD /*implementation defined*/ |
(desde C++11) | |
| #define FE_TONEAREST /*implementation defined*/ |
(desde C++11) | |
| #define FE_TOWARDZERO /*implementation defined*/ |
(desde C++11) | |
| #define FE_UPWARD /*implementation defined*/ |
(desde C++11) | |
Cada una de estas constantes macro se expande a un número entero no negativo expresión constante, que puede utilizarse con me std::fesetround y std::fegetround para indicar uno de los modos de redondeo compatibles de punto flotante. La aplicación puede definir adicionales constantes modo de redondeo en
<cfenv>, que todo debe comenzar con FE_ seguido por al menos una letra mayúscula. Cada macro se define sólo si es respaldada .Original:
Each of these macro constants expands to a nonnegative integer constant expression, which can me used with std::fesetround and std::fegetround to indicate one of the supported floating-point rounding modes. The implementation may define additional rounding mode constants in
<cfenv>, which should all begin with FE_ followed by at least one uppercase letter. Each macro is only defined if it is supported.The text has been machine-translated via Google Translate.
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En la mayoría de las implementaciones, estas constantes macro ampliar a los valores iguales a los valores de FLT_ROUNDS y std::float_round_style
Original:
On most implementations, these macro constants expand to the values equal to the values of FLT_ROUNDS and std::float_round_style
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| Constant
Original: Constant The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Explanation |
FE_DOWNWARD
|
redondeo hacia el infinito negativo
Original: rounding towards negative infinity The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
FE_TONEAREST
|
redondeo hacia entero más cercano
Original: rounding towards nearest integer The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
FE_TOWARDZERO
|
redondeo hacia cero
Original: rounding towards zero The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
FE_UPWARD
|
redondeo hacia el infinito positivo
Original: rounding towards positive infinity The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Modos adicionales de redondeo puede estar avalado por una implementación .
Original:
Additional rounding modes may be supported by an implementation.
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[editar] Ejemplo
Ejecuta este código
#include <cmath> #include <cfenv> #include <iostream> int main() { #pragma STDC FENV_ACCESS ON std::fesetround(FE_DOWNWARD); std::cout << "rounding using FE_DOWNWARD: \n" << std::fixed << " 12.0 -> " << std::nearbyint(12.0) << '\n' << " 12.1 -> " << std::nearbyint(12.1) << '\n' << "-12.1 -> " << std::nearbyint(-12.1) << '\n' << " 12.5 -> " << std::nearbyint(12.5) << '\n' << " 12.9 -> " << std::nearbyint(12.9) << '\n' << "-12.9 -> " << std::nearbyint(-12.9) << '\n' << " 13.0 -> " << std::nearbyint(13.0) << '\n'; std::fesetround(FE_TONEAREST); std::cout << "rounding using FE_TONEAREST: \n" << " 12.0 -> " << std::nearbyint(12.0) << '\n' << " 12.1 -> " << std::nearbyint(12.1) << '\n' << "-12.1 -> " << std::nearbyint(-12.1) << '\n' << " 12.5 -> " << std::nearbyint(12.5) << '\n' << " 12.9 -> " << std::nearbyint(12.9) << '\n' << "-12.9 -> " << std::nearbyint(-12.9) << '\n' << " 13.0 -> " << std::nearbyint(13.0) << '\n'; }
Salida:
rounding using FE_DOWNWARD: 12.0 -> 12.000000 12.1 -> 12.000000 -12.1 -> -13.000000 12.5 -> 12.000000 12.9 -> 12.000000 -12.9 -> -13.000000 13.0 -> 13.000000 rounding using FE_TONEAREST: 12.0 -> 12.000000 12.1 -> 12.000000 -12.1 -> -12.000000 12.5 -> 12.000000 12.9 -> 13.000000 -12.9 -> -13.000000 13.0 -> 13.000000
[editar] Ver también
| Indica modalidades de redondeo de punto flotante. (enum) | |
| (C++11)(C++11) |
Obtiene o establece la dirección redondeo (función) |
