CODEWITHSUNDEEP
c++cstringcompare
Ren
Ren

Reputation: 4683

What is the proper function for comparing two C-style strings?

So I have a dilemma. I need to compare two C-style strings and I searched for the functions that would be the most appropiate:

memcmp   //Compare two blocks of memory (function)
strcmp   //Compare two strings (function )
strcoll  //Compare two strings using locale (function)
strncmp  //Compare characters of two strings (function)
strxfrm  //Transform string using locale (function)

The first one I think is for addresses, so the idea is out. The second one sounds like the best choice to me, but I wanna hear feedback anyway. The other three leave me clueless.

Upvotes: 9

Views: 6169

Answers (2)

Carl Norum
Carl Norum

Reputation: 224962

Both memcmp and strcmp will work fine. To use the former, you'll need to know the length of the shorter string in advance.

Upvotes: 4

templatetypedef
templatetypedef

Reputation: 372814

For general string comparisons, strcmp is the appropriate function. You should use strncmp to only compare some number of characters from a string (for example, a prefix), and memcmp to compare blocks of memory.

That said, since you're using C++, you should avoid this altogether and use the std::string class, which is much easier to use and generally safer than C-style strings. You can compare two std::strings for equality easily by just using the == operator.

Hope this helps!

Upvotes: 27

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