static T infinity();
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(C++11 前) | |
static constexpr T infinity();
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(C++11 起) | |
返回浮点类型 T
所表示的特殊值“正无穷大”。仅若 std::numeric_limits<T>::has_infinity == true 才有意义。在 IEEE 754 ,最常见的浮点数二进制表示中,正无穷大是拥有所有指数位被设置而所有尾数位被清除的值。
目录 |
T
|
std::numeric_limits<T>::infinity() |
/* non-specialized */ | T();
|
bool | false |
char | 0 |
signed char | 0 |
unsigned char | 0 |
wchar_t | 0 |
char16_t | 0 |
char32_t | 0 |
short | 0 |
unsigned short | 0 |
int | 0 |
unsigned int | 0 |
long | 0 |
unsigned long | 0 |
long long | 0 |
unsigned long long | 0 |
float | HUGE_VALF |
double | HUGE_VAL |
long double | HUGE_VALL |
(无) | (C++11 前) |
noexcept 规定:
noexcept
|
(C++11 起) |
#include <iostream> #include <limits> int main() { double max = std::numeric_limits<double>::max(); double inf = std::numeric_limits<double>::infinity(); if(inf > max) std::cout << inf << " is greater than " << max << '\n'; }
输出:
inf is greater than 1.79769e+308
[静态]
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鉴别能表示特殊值“正无穷大”的浮点类型 (公开静态成员常量) |