public member function
<forward_list>
bool empty() const noexcept;
Test whether array is empty
返回一个boolvalue indicating whether the forward_list container is empty, i.e. whether its size is0.
This function does not modify the content of the container in any way. To clear the content of an array object, see forward_list::clear.
返回值
true如果容器大小为0, false否则为 false。
示例
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// forward_list::empty
#include <iostream>
#include <forward_list>
int main ()
{
std::forward_list<int> first;
std::forward_list<int> second = {20, 40, 80};
std::cout << "first " << (first.empty() ? "is empty" : "is not empty" ) << std::endl;
std::cout << "second " << (second.empty() ? "is empty" : "is not empty" ) << std::endl;
return 0;
}
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输出
first is empty
second is not empty
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数据竞争
访问容器。
不访问任何包含的元素：并发访问或修改它们是安全的。