在 C++ 替代方案中检查空字符串
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Checking for empty string in C++ alternatives
提问by fgalan
There are (at least :) two ways of checking if an string is empty in C++, in particular:
在 C++ 中有（至少 :）两种检查字符串是否为空的方法，特别是：
if (s.length() == 0) {
// string is empty
}
and
和
if (s == "") {
// string is empty
}
Which one is the best from a performance point of view? Maybe the library implementation is clever enough so there isn't any different between them (in which case other criteria should decide, i.e. readibility) but I tend to think that the first alternative (using length()) is better.
从性能的角度来看，哪个是最好的？也许库的实现足够聪明，所以它们之间没有任何区别（在这种情况下应该由其他标准决定，即可读性），但我倾向于认为第一个选择（使用length()）更好。
Any feedback on this, please? (Or even a 3rd method better than the ones I have proposed).
请对此有任何反馈吗？（或者甚至是比我提出的方法更好的第三种方法）。
回答by artm
You can also use empty
你也可以使用 empty
if(s.empty())
回答by fgalan
You can use the following:
您可以使用以下内容：
s.empty();
s.size() == 0;
!s.size();
