std::numeric_limits<T>::infinity
< cpp | types | numeric limits
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static T infinity() throw();
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(C++11 前) | |
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static constexpr T infinity() noexcept;
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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。在最常见的浮点数二进制表示 IEEE 754 中，正无穷大是所有指数位为 1 而所有尾数位为 0 的值。
返回值
T |
std::numeric_limits<T>::infinity() |
| /* non-specialized */ | T() |
| bool | false |
| char | 0 |
| signed char | 0 |
| unsigned char | 0 |
| wchar_t | 0 |
| char8_t (C++20) | 0 |
| char16_t (C++11) | 0 |
| char32_t (C++11) | 0 |
| short | 0 |
| unsigned short | 0 |
| int | 0 |
| unsigned int | 0 |
| long | 0 |
| unsigned long | 0 |
| long long (C++11) | 0 |
| unsigned long long (C++11) | 0 |
| float | HUGE_VALF |
| double | HUGE_VAL |
| long double | HUGE_VALL |
示例
#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
参阅
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[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) |