Printing integer with TextOut()

Dev Shed Forums Sponsor:

May 24th, 2010, 01:00 AM

echelon

Registered User

Join Date: May 2010

Location: Finland

Posts: 4

Time spent in forums: 1 h 43 m 42 sec
Reputation Power: 0

Printing integer with TextOut()

Hi everyone,

I'm programming a Tetris clone with Visual C++ and my problem is printing score with TextOut() function. I've created a generic template class for string conversion and trying to use stringstream to help with conversion. Here's the code I've come up with:

Code:

template <class T>
std::string to_string(T t, std::ios_base & (*f)(std::ios_base&))
{
  std::ostringstream outputStream;
  outputStream << f << t;
  return outputStream.str();
}

LPCTSTR lpString = "Score:";
LPCTSTR stBuffer;
int iScore = 0;
std::stringstream oss;
stBuffer << to_string <int> (iScore, std::dec);
stBuffer = (LPCTSTR)oss.str();


TextOut(hdc, 175, 350, stBuffer, strlen(stBuffer));

Above technique works fine in the console, but when trying to make it work on Windows application, the code won't even compile. Any ideas to help with the current code? Or maybe completely different approach to print out the score?

May 24th, 2010, 01:15 AM

DaWei_M

Lord of Dorkness

Dev Shed God 8th Plane (8500 - 8999 posts)

Join Date: Jan 2004

Location: Central New York. Texan via Arizona, out of his element!

Posts: 8,515

Time spent in forums: 4 Weeks 18 h 59 m 31 sec
Warnings Level: 20
Number of bans: 3
Reputation Power: 3268

Exactly how did you try to move this to a GUI environment? The code you show is, quite frankly, worthless.

A console app is, generally speaking, a series of steps from here to there. A GUI app is more likely to be driven by events. It isn't a tough transition, but its different.

Comments on this post

echelon disagrees!

__________________
Functionality rules and clarity matters; if you can work a little elegance in there, you're stylin'.
If you can't spell "u", "ur", and "ne1", why would I hire you? 300 baud modem? Forget I mentioned it.
DaWei on Pointers Politically Incorrect.

May 24th, 2010, 01:27 AM

echelon

Registered User

Join Date: May 2010

Location: Finland

Posts: 4

Time spent in forums: 1 h 43 m 42 sec
Reputation Power: 0

I do text drawing in the TheWindowProc CALLBACK function when receiving message WM_PAINT. My WM_PAINT event handling is as follows.

Code:

case WM_PAINT:
{
	PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd,&ps);
	BitBlt(hdc, 0, 0, TILESIZE*MAPWIDTH+TILESIZE*GREY, TILESIZE*MAPHEIGHT, bmoMap, 0, 0, SRCCOPY);
	LPCTSTR lpString = "Score:";
	LPCTSTR stBuffer;
	int iScore = 0;
	std::stringstream oss;
	stBuffer << to_string <int> (iScore, std::dec);
	stBuffer = (LPCTSTR)oss.str();			
				
	TextOut(hdc, 175, 300, lpString, 6);				

	TextOut(hdc, 175, 350, stBuffer, strlen(stBuffer));				

	EndPaint(hwnd, &ps);
	return 0;
} break;

First TextOut which prints out the string "Score:" works fine, so the actual problem is somehow to convert int to LPSTRING.

May 24th, 2010, 01:59 AM

echelon

Registered User

Join Date: May 2010

Location: Finland

Posts: 4

Time spent in forums: 1 h 43 m 42 sec
Reputation Power: 0

Ok, I was able to figure it out. The solution was as simple as just use sprintf in the following way...

Code:

sprintf(stBuffer, "%i", iScore);

...and then just print stBuffer with TextOut.

May 24th, 2010, 10:44 AM

salem

Contributed User

Join Date: Jun 2005

Posts: 3,909

Folding Points: 153 Folding Title: Novice Folder

Time spent in forums: 2 Months 3 Weeks 4 Days 2 h 4 m 37 sec
Reputation Power: 1774

http://msdn.microsoft.com/en-us/lib...28VS.85%29.aspx

Quote:

LPCSTR
Pointer to a constant null-terminated string of 8-bit Windows (ANSI) characters. For more information, see Character Sets Used By Fonts.

This type is declared in WinNT.h as follows:

Code:

typedef __nullterminated CONST CHAR *LPCSTR;

LPCTSTR

An LPCWSTR if UNICODE is defined, an LPCSTR otherwise.

This type is declared in WinNT.h as follows:

Code:

#ifdef UNICODE
 typedef LPCWSTR LPCTSTR; 
#else
 typedef LPCSTR LPCTSTR;
#endif

> sprintf(stBuffer, "%i", iScore);
1. If you didn't allocate any space for this (it's just a raw pointer of some sort), you've just trashed some memory.
Sooner or later, this will crash - mostly close to the release deadline (or in a demo) for various unexplained reasons.

2. You've declared it as the "T" variant of the type, which means everything changes automatically if you enable UNICODE.
But that only works if you've used all the other UNICODE wrappers for all the functions which use said variables.

Comments on this post

echelon agrees: Thanks!

__________________
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper

Printing integer with TextOut()

Developer Shed Advertisers and Affiliates