Klaim Klaim - 3 months ago 24
C++ Question

Differences between C++ string == and compare()?

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.

Answer

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!