Why doesnt this memcmp work???

[tgreaves]

Im new to c++ so bare with me.. This code compiles but it doesnt stop when they are equal.. Whats my problem?

static TCHAR * szUp      = TEXT ("Up") 
TCHAR szKeyName[32];

if (memcmp(szKeyName, szUp, 2)) {
  s_selected[mapSudokuBoard[hwnd]] = 0 ;
  SetFocus (s_window[mapSudokuBoard[hwnd] - 9]);
}

[GCDEF]

Have you checekd the return values for memcmp? 0 indicates equality.

Wouldn't strcmp be better here?

[tgreaves]

I havent checked the values as of yet.. My boss is a c++ programmer and thats just what he told me to use.. Ill check out strcmp also..

[VictorN]

Wouldn't strcmp be better here?

Sure, you meant _tcscmp

[tgreaves]

Very strange.. This code below works..

         iMyInt = memcmp(szKeyName, szUp, 2);
         if (iMyInt == 0) {
           s_selected[mapSudokuBoard[hwnd]] = 0 ;
           SetFocus (s_window[mapSudokuBoard[hwnd] - 9]);
		 }

Any ideas whats wrong with my first bit of code at the top?

[GCDEF]

Very strange.. This code below works..

         iMyInt = memcmp(szKeyName, szUp, 2);
         if (iMyInt == 0) {
           s_selected[mapSudokuBoard[hwnd]] = 0 ;
           SetFocus (s_window[mapSudokuBoard[hwnd] - 9]);
		 }

Any ideas whats wrong with my first bit of code at the top?

Sure. In the first you're testing for non-zero, in the second you're testing for zero.

Change the first one to

if (memcmp(szKeyName, szUp, 2) == 0)
{
  s_selected[mapSudokuBoard[hwnd]] = 0 ;
  SetFocus (s_window[mapSudokuBoard[hwnd] - 9]);
}

and it will work too.

[GCDEF]

Sure, you meant _tcscmp

In all the years I've been doing this, Unicode has never been an issue I've ever had to think about. Maybe it's just me. FWIW, selecting _tcscmp documentation in MSDN brings up strcmp documentation.

[tgreaves]

Sure. In the first you're testing for non-zero, in the second you're testing for zero.

Change the first one to

if (memcmp(szKeyName, szUp, 2) == 0)
{
  s_selected[mapSudokuBoard[hwnd]] = 0 ;
  SetFocus (s_window[mapSudokuBoard[hwnd] - 9]);
}

and it will work too.

I thought "if (!memcmp(szKeyName,szUp,2))" was testing for not zero???

[GCDEF]

Sigh. It is. That's why I add == 0 to the if statement.

A return of 0 indicates equality. You're testing to see if the different.

[Lindley]

In all the years I've been doing this, Unicode has never been an issue I've ever had to think about.

Consider yourself fortunate.

[STLDude]

I havent checked the values as of yet.. My boss is a c++ programmer and thats just what he told me to use.. Ill check out strcmp also..

Then why not using std::string?

std::string stringOne ="Blah";
std::string stringTwo ="Nada";
if (stringOne == stringTwo)
{
   // string are the same
}
else
{
   // strings are not the same
}