FE_DOWNWARD, FE_TONEAREST, FE_TOWARDZERO, FE_UPWARD
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<metanoindex/>
<tbody> </tbody>| Definido no cabeçalho <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 uma destas constantes macro expande para uma expressão inteiro não negativo constante, o que pode me usado com std::fesetround e std::fegetround para indicar um dos modos suportados de ponto flutuante de arredondamento. A aplicação pode definir constantes de modo adicional de arredondamento em
<cfenv>, que devem todos começam com FE_ seguido por pelo menos uma letra maiúscula. Cada macro é definida somente se for suportado.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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Na maioria das implementações, estas constantes de macro expandir-se para os valores iguais aos valores do FLT_ROUNDS e 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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Constante
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
|
arredondamento para o 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
|
arredondamento para o inteiro mais próximo
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
|
arredondamento para zero
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
|
arredondamento para o 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. |
Arredondamento modos podem ser suportados por uma implementação.
Original:
Additional rounding modes may be supported by an implementation.
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You can help to correct and verify the translation. Click here for instructions.
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Exemplo
#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';
}
Saída:
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
Veja também
indica os modos de ponto flutuante de arredondamento Original: indicates floating-point rounding modes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (enum) | |
(C++11) (C++11) |
obtém ou define direção arredondamento Original: gets or sets rounding direction The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função) |