Can't i find Keyvalue of map container TCHAR* using TCHAR[]?

Question

#include<iostream>
#include<map>

using namesapce std;
void main()
{
   map<const TCHAR*, int> Map;
   Map.insert(make_pare(L"DOG1",1));
   Map.insert(make_pare(L"DOG2",2));

   TCHAR szTem[128];
   wsprintf(szTem,L"DOG%d",1);

   map<const TCHAR*, int>::iterator iter = Map.find(szTem);

   cout << iter->second << endl;
}

Like this case, I couldn't find TCHAR* Keyvalue using TCHAR[]. Why i can't do this, and how can i find pointer string Keyvalue using string that include integer fomula?

because the comparison operator `<` isn't defined for TCHAR* to dereference the pointer and compare string values, it's going to compare the pointer address values which is incorrect. You need to define the comparator or use `std::string` is there a reason you need to use `TCHAR` here? — EdChum, Nov 14 '16 at 15:09
You didn't define `TCHAR`. If you use non-standard features, you should tell us which os/compiler/standard library you are targetting. `void main` is not standard either. — eerorika, Nov 14 '16 at 15:16

score 2 · Accepted Answer · edited May 23 '17 at 12:24

2

You can not do that, because default map comparator will compare TCHAR pointers, which of course would be different. Best approach would be to use std::wstring instead. If you insist on using TCHAR pointer, you have to provide custom comparator.

edited May 23 '17 at 12:24

Community

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answered Nov 14 '16 at 15:09

Ari0nhh

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What if `TCHAR` isn't `wchar_t`? – eerorika Nov 14 '16 at 15:23
Then use `std::string`, or define a macro in case you need to support *both* kinds of strings. – Ari0nhh Nov 14 '16 at 15:25
You don't need a macro. Simply use `std::basic_string` to support any `TCHAR`. – eerorika Nov 14 '16 at 15:39

Can't i find Keyvalue of map container TCHAR* using TCHAR[]?

1 Answers1