C ++ string ==和compare（）之间的区别？ [英] Differences between C++ string == and compare()?

问题描述

我只是看一些关于使用

的建议。

  std :: string s = get_string 
 std :: string t = another_string（）; 
 
 if（！s.compare（t））
 {
  

而不是

  if（s == t）
 {
  

我几乎总是使用最后一个，因为我习惯了它，它感觉自然，更可读。我甚至不知道有一个单独的比较函数。
为了更精确，我认为==会调用compare（）。

有什么区别？在哪个上下文中应该以另一种方式偏好？

我只考虑我需要知道一个字符串是否相同的情况作为另一个字符串。

解决方案

这是标准对 operator ==

21.4.8.2 operator ==

  template< class charT，class traits，class Allocator> 
 bool operator ==（const basic_string< charT，traits，Allocator>& lhs，
 const basic_string< charT，traits，Allocator>& rhs）noexcept; 
  

返回：lhs.compare（rhs）== 0。 p>

看起来没什么区别！

I just read some recommendations on using

std::string s = get_string();
std::string t = another_string();

if( !s.compare(t) ) 
{

instead of

if( s == t )
{

I'm almost always using the last one because I'm used to it and it feels natural, more readable. I didn't even know that there was a separate comparison function. To be more precise, I thought == would call compare().

What are the differences? In which contexts should one way be favored to the other?

I'm considering only the cases where I need to know if a string is the same value as another string.

解决方案

This is what the standard has to say about operator==

21.4.8.2 operator==

template<class charT, class traits, class Allocator>
bool operator==(const basic_string<charT,traits,Allocator>& lhs,
                const basic_string<charT,traits,Allocator>& rhs) noexcept;

Returns: lhs.compare(rhs) == 0.

Seems like there isn't much of a difference!

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