Thread: 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.

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.

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;

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