std::basic_string::empty
bool empty() const; | | |
|---|
检查字符串是否没有字符，即是否begin() == end()...
参数
%280%29
返回值
true如果字符串是空的，false否则。
例外
(none) | (until C++11) |
|---|---|
noexcept specification: noexcept | (since C++11) |
复杂性
常量。
例
二次
#include <iostream>
#include <string>
int main()
{
std::string s;
std::boolalpha(std::cout);
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
s = "Exemplar";
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
s = "";
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
}二次
产出：
二次
s.empty():true s:''
s.empty():false s:'Exemplar'
s.empty():true s:''二次
另见
sizelength | returns the number of characters (public member function) |
|---|
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