Textprint_ex and strings

Textprint_ex and strings

Raf Vermeulen

Member #7,166

April 2006

Hey, I'm trying to print a string using textprint_ex, but whenever I get to the line of code that does that, the program crashes. The string itself shows fine in a console window when doing cout.

The line of code I use, is this:
textprintf_ex(buffer, font, 100, y, makecol(255, 255, 255), -1, "%s", test);

Anybody knows why it crashes, and how to fix it?

Kauhiz

Member #4,798

July 2004

Let's see some more code.

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It's Ridge Racer! RIIIIIDGE RAAAAACER!

Raf Vermeulen

Member #7,166

April 2006

1void load_highscores() {
   int y = 50;
   string line;
   string test = "TEST";
   ifstream file ("High.txt");
   if (file.is_open()) {
      while (!file.eof()){
            getline (file,line);
            cout << test << "\n";
            textprintf_ex(buffer, font, 100, y, makecol(255, 255, 255), -1, "%s", test);
            y += 20;
      }
      file.close();
  }
15}

When I comment out the textprintf_ex command, it all works smoothly, but with that command, it crashes.

Kauhiz

Member #4,798

July 2004

That's because textprintf_ex wants a C-string, not a std::string. I'm surprised that even compiles.

---
It's Ridge Racer! RIIIIIDGE RAAAAACER!

X-G

Member #856

December 2000

It compiles because variadic functions don't typecheck "..." arguments.

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Kauhiz

Member #4,798

July 2004

Good to know.

---
It's Ridge Racer! RIIIIIDGE RAAAAACER!

HoHo

Member #4,534

April 2004

instead of test use test.c_str()

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Raf Vermeulen

Member #7,166

April 2006

That works like a charm, the .c_str():D Thanks for the help!

Kikaru

Member #7,616

August 2006

.c_str() returns a char array (C-style string) just like the string you used it on. Just felt the need to point that out.

Kitty Cat

Member #2,815

October 2002

Quote:

It compiles because variadic functions don't typecheck "..." arguments.

It does if you add the printf attribute to the function. So either MSVC doesn't have a way to check it and he's using MSVC, or he has warnings off.

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Raf Vermeulen

Member #7,166

April 2006

Warnings're turned on. Compiler's standard one in Dev-C++ (with the Allegro parameter).

Neil Black

Member #7,867

October 2006

Figuring out how to print strings got me so frustrated. I still have no idea where anyone could find out they had to add .c_str() to their string variable. I'm just glad someone on the forums knew.

GullRaDriel

Member #3,861

September 2003

Possumdude0 said:

I still have no idea where anyone could find out they had to add .c_str() to their string variable.

Google is your friend. Or your favorite porn search engine .

"Code is like shit - it only smells if it is not yours"
Allegro Wiki, full of examples and articles !!

Neil Black

Member #7,867

October 2006

GullRaDriel: wow, you've answered almost every one of my posts today!

gnolam

Member #2,030

March 2002

Quote:

I still have no idea where anyone could find out they had to add .c_str() to their string variable.

From wherever you were supposed to have learned C++.

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Neil Black

Member #7,867

October 2006

I learned C++ from gamedev.net, and a little right here.

HoHo

Member #4,534

April 2004

Get a good free C++ book. I learnt about .c_str() from the one that should be on the first link, "thinking in C++" by Bruce Eckel.

GullRaDriel

Member #3,861

September 2003

Possumdude0: It's because I got nothing else to do today.

I second HoHo and Gnolam thought.

"Code is like shit - it only smells if it is not yours"
Allegro Wiki, full of examples and articles !!