asked on

Convert CString to char for use in Switch

I know that I can't use a CString in a switch statement, but I only need to do a comparison against the first letter of the string. I can not figure out how to take the letter from the CString and put it into a char so I can use it in switch statement.

This seems like a simple thing to do, but all searches on CString and char pull up char pointers and that is what I am trying to get away from.

Thanks in advance.

jkr

>> I can not figure out how to take the letter from the CString
>>and put it into a char so I can use it in switch statement

Use

CString str ( "test");
char* pc = (LPCTSTR) str;

switch ( *pc) {

case 'a':

//...

break;

//....

case 't':

break;
};

jkr

To elaborate on the above - the docs explain 'operator LPCTSTR()' as follows:

--------------->8-----------------------------

CString::operator LPCTSTR
operator LPCTSTR ( ) const;

Return Value

A character pointer to the string’s data.

Remarks

This useful casting operator provides an efficient method to access the null-terminated C string contained in a CString object. No characters are copied; only a pointer is returned. Be careful with this operator. If you change a CString object after you have obtained the character pointer, you may cause a reallocation of memory that invalidates the pointer.

--------------->8-----------------------------

So, if you have acces to the contents through a char*, you can dereference the pointer using '*pc' to access the first character.

APlusComp247

ASKER

This is part of the code that I am use

szFileName = data.cFileName;
      szFirstLetter.Format("%s",szFileName.Left(1));
      szFirstLetter.MakeLower();
      char* cLetter = (LPCTSTR) szFirstLetter;

      switch (*cLetter)
      {
      case 'a':
       m_nCount[1] ++;
      default:
       m_nCount[0] ++;
      }

I get the following error.

error C2440: 'initializing' : cannot convert from 'const char *' to 'char *'
Conversion loses qualifiers

Thanks for the prompt reply

ASKER CERTIFIED SOLUTION

jkr

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APlusComp247

ASKER

That works great!!!! Thank you so much for you quick responces!

TiCpu

Better would be :
char cLetter = sTextYouWantFirstLetter.GetAt(0);

APlusComp247

ASKER

TiCpu
Thanks a lot for the post. I am by no means a C++/MFC pro and really appreciate all the little shortcuts that I can pick up. I really thought that there should be an easier way to do that, and sure enough you showed me.

Thanks again!

WilimarLynwood

I'd use

CString str = "SomeString";

switch (str[0]) //0 so we point to the first char
{
case 'S':
//stuff
break;
default:
//other stuff
break;
}