std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>:: clear
From cppreference.net
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Containers library
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(C++26)
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(C++23)
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(C++23)
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(C++23)
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(C++20)
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(C++23)
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std::flat_map
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void
clear
(
)
noexcept
;
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(自 C++23 起)
(自 C++26 起为 constexpr) |
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从容器的适配器中擦除所有元素。此调用后， size() 返回零。
使所有指向容器元素的引用、指针和迭代器失效。
复杂度
线性于容器适配器的大小，即元素的数量。
示例
运行此代码
#include <iostream> #include <string_view> #include <flat_map> void print_info(std::string_view rem, const std::flat_map<int, char>& v) { std::cout << rem << "{ "; for (const auto& [key, value] : v) std::cout << '[' << key << "]:" << value << ' '; std::cout << "}\n"; std::cout << "Size=" << v.size() << '\n'; } int main() { std::flat_map<int, char> container{{1, 'x'}, {2, 'y'}, {3, 'z'}}; print_info("Before clear: ", container); container.clear(); print_info("After clear: ", container); }
输出：
Before clear: { [1]:x [2]:y [3]:z }
Size=3
After clear: { }
Size=0
参见
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擦除元素
(公开成员函数) |