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C++ keyword: long

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用法

示例

#include <climits>
#include <concepts>
#include <iostream>
#include <limits>
#include <locale>
static_assert(
    sizeof(long) >= 32 / CHAR_BIT &&
    sizeof(unsigned long) >= 32 / CHAR_BIT &&
    std::numeric_limits<long>::min() <= -2'147'483'647l - 1 && //'
    std::numeric_limits<long>::max() >= 2'147'483'647l && //'
    std::numeric_limits<unsigned long>::max() >= 4'294'967'295ul); //'
// 'long long' 和 'unsigned long long' 自 C++11 起可用
static_assert(
    sizeof(long long) >= 64 / CHAR_BIT &&
    sizeof(unsigned long long) >= 64 / CHAR_BIT &&
    std::numeric_limits<long long>::min() <= -9'223'372'036'854'775'807ll - 1 &&
    std::numeric_limits<long long>::max() >= 9'223'372'036'854'775'807ll &&
    std::numeric_limits<unsigned long long>::max() >= 18'446'744'073'709'551'615ull);
// 概念自 C++20 起可用
static_assert(
    std::integral<long> &&
    std::integral<long long> &&
    std::integral<unsigned long> &&
    std::integral<unsigned long long> &&
    std::floating_point<long double>);
// 注意 'long' 不能修饰 'float'
static_assert(
    std::same_as<decltype(0l), signed long int> &&
    std::same_as<decltype(0ll), signed long long int> &&
    std::same_as<decltype(0ul), unsigned long int> &&
    std::same_as<decltype(0ull), unsigned long long int> &&
    std::same_as<decltype(0.l), long double>);
template <typename T, typename... Ts>
concept all_same = (... and std::same_as <T, Ts>);
static_assert(
    all_same<long, long int, signed long, signed long int> &&
    all_same<unsigned long, unsigned long int> &&
    all_same<long long, long long int, signed long long, signed long long int> &&
    all_same<unsigned long long, unsigned long long int>);
#define OUT(...) std::cout << #__VA_ARGS__ << " = " << __VA_ARGS__ << '\n'
int main()
{
    std::cout.imbue(std::locale("en_US.UTF-8"));
    OUT(sizeof(long));
    OUT<span class="br

参见