Making a CString map case insensitive

This is a discussion on Making a CString map case insensitive within the C++ Programming forums, part of the General Programming Boards category; Hello, I've tried to figure this out, but so far I haven't succeeded. I have a program that uses CStrings, ...

  1. #1
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    Making a CString map case insensitive

    Hello,

    I've tried to figure this out, but so far I haven't succeeded. I have a program that uses CStrings, and at one point there's a definition of a map: std::map<CString, CUser>
    Somewhere else in the program the map is being iterated. I want to make the map case insensitive so it will output every CString in the correct lexicographic order, no matter what case it's in.
    So when definining the map I now put std::map<CString, CUser, class Cmp = NoCase<CString>>. However I don't know how to define a lesser than compare operator for CStrings.

    I never used C-style strings before so I'm in the need of some help on how to solve this.
    Thanks a lot if you can help me out,

    Edward.

  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    look up CString::CompareNoCase() at msdn or in your helpfiles. BTW this qualifies as windows programming so for mfc questions use the windows forum.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  3. #3
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    However I don't know how to define a lesser than compare operator for CStrings.
    Hi,

    A comparison function for strings starts at the beginning of each string and examines each character's ascii code. What you could do is use tolower() to change each character in a string to lower case, and then use the comparison functions that are already defined for strings, e.g strcmp() for cstrings or <, =, or > for C++ string's.

  4. #4
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    Here is one I used:
    Code:
    namespace
    {
     struct CStringCompareNoCaseLessThan
     {
      bool operator()(const CString& lhs, const CString& rhs) const
      {
       return lhs.CompareNoCase(rhs) < 0;
      }
     };
    };
     
    typedef std::map<CString, CUser, CStringCompareNoCaseLessThan> mapNameToUser;

  5. #5
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    I'd suggest a class template. Override the < 'z' or > 'A' operators. Take my suggestion as incomplete. I need a cigaret.

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