C++ help

[Woozie]

As those of you who read spam or visit Shue's IRC may already know, I really really really suck at programming.

So someone from the physics department who found out I suck at programming helped me find a good book on how to program.

I'm only on the second chapter and I'm already stuck. I'm using microsoft visual c++ 2008 express edition. I'm taking a program straight from the book with no modifications at all whatsoever and I'm getting errors.

 1  // Fig. 2.1: fig02_01.cpp
 2  // Text-printing program.
 3  #include <iostream> // allows program to output data to the screen
 4
 5  // function main begins program execution
 6  int main()
 7  {
 8     std::cout << "Welcome to C++!\n"; // display message
 9
10     return 0; // indicate that program ended successfully
11
12  } // end function main

This is a direct copy/paste from the electronic version of this book. When I compile, I get

Practice.cpp
c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\practice\practice.cpp(1) : error C2059: syntax error : 'constant'
c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\practice\practice.cpp(3) : error C2014: preprocessor command must start as first nonwhite space
c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\practice\practice.cpp(7) : error C2143: syntax error : missing ';' before '{'
c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\practice\practice.cpp(7) : error C2447: '{' : missing function header (old-style formal list?)
Build log was saved at "file://c:\Documents and Settings\Lawrenzo\My Documents\Visual Studio 2008\Projects\Practice\Practice\Debug\BuildLog.htm "
Practice - 4 error(s), 0 warning(s)

Four errors. I figured that somehow the numbering was causing them so I changed it to

// Fig. 2.1: fig02_01.cpp
// Text-printing program.
#include <iostream> // allows program to output data to the screen
 // function main begins program execution
int main()
 {
std::cout << "Welcome to C++!\n"; // display message
return 0; // indicate that program ended successfully
} // end function main

and I get

Practice - 0 error(s), 0 warning(s)
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

So it would seem that it was successful, but I'm not getting any output at all. It doesn't say "Welcome to C++!" anywhere. If I go to compile instead of build, I get the exact same thing. This problem is probably due to the fact that I have no clue how to use microsoft visual c++ 2008 express. Can anyone either explain to me what I'm doing wrong/how to do it right or tell me about another free C++ compiler that would be easier for a beginner to understand?

[Xanthe]

Your project is working as intended. The only issue is that the console window closes immediately after the program finishes running so you never see the output. Try opening a command window and navigate <project folder> > Debug. Then run <project name>.exe. You should be able to see your output now.

[Zosi]

No, compile/build doesn't run the program after it finishes compiling, which is his first problem. Go to Debug -> Start Debugging to watch your program run.

However, as Xanthe posted, it'll print the line and close the program quickly. Change it to this:

// Fig. 2.1: fig02_01.cpp
// Text-printing program.
#include <iostream> // allows program to output data to the screen
 // function main begins program execution
int main()
 {
std::cout << "Welcome to C++!\n"; // display message
system("PAUSE");
return 0; // indicate that program ended successfully
} // end function main

The book probably won't explain it, so I will. The system("PAUSE"); line just displays a "Press any key to continue..." and waits for a keypress so you can read the output of the program before it closes.

[Eanae]

You know if you ever need help Woozie, there's 5 or 6 of us who know their stuff in Shue's irc channel.

[Woozie]

Is there any way to make it print the line and not close up quickly (other than the pause thingy)? Like is there a default setting that would make the window stay open so that I can actually read the text then close the window myself?

edit:

Your project is working as intended. The only issue is that the console window closes immediately after the program finishes running so you never see the output. Try opening a command window and navigate <project folder> > Debug. Then run <project name>.exe. You should be able to see your output now.

I don't know how to navigate any folders from the command window.

[Mizango]

You know if you ever need help Woozie, there's 5 or 6 of us who know their stuff in Shue's irc channel.

^ Ding Ding Ding! And on Yahoo *cough *cough

[Woozie]

You're never online anyways, Mizango D:

[Fhqwghads]

while(1);

There ya go, infinite pause.

lol

[Devek]

I don't know.. programming is kind of pointless unless you start young and can figure stuff out by yourself.

[Purrrfect]

I don't know how to navigate any folders from the command window.

You just need someone to set up a machine with something like dos 6 on it and hide all your porn on there! Then you'll learn how to navigate in a command prompt lol. I agree the command window closing on exit is kind of annoying for beginning programming.

[Devek]

You just need someone to set up a machine with something like dos 6 on it and hide all your porn on there! Then you'll learn how to navigate in a command prompt lol. I agree the command window closing on exit is kind of annoying for beginning programming.

Microsoft's IDE doesn't have a console window like every single IDE in the entire world does?

Maybe he should use something better.

Example:

http://img11.imageshack.us/img11/7429/anjuta.png

[Zhais]

Microsoft's IDE doesn't have a console window like every single IDE in the entire world does?

Maybe he should use something better.

It does, it just closes when the end of the program is reached. It's not open all the time (maybe changeable).

[Devek]

Look at the picture above, that is what is called a console window.

[MisterBob]

Both Visual Studio 2005 and 2008 have console windows that do not close automatically if you are using the proper settings. You could also just set a breakpoint in your code. (If you're not aware how to do that, learn now. It's invaluable)

[Vic]

How many programming languages do you need to learn Woozie?

First anyways with vs 2008 you don't need to have std:: in front of cin or cout if you put using namespace std; in front of the main() class.

There are two simple solutions to preventing the console window from closing: first is to place cin.get(); at the end of the code block. This will require enter to be pressed before the program can finish.
The second and more efficient way, especially with a program that simple is to run the program without debugging.

[Teorem]

I figured that somehow the numbering was causing them so I changed it to...

Looking at the way you worded this, do you understand why the numbers were causing it to fail though? The example number looks like you're using a Deitel & Deitel text, which means all of the example code should be formatted the same: the numbers on each line are a reference to be used by you as they describe the contents of each example (and thus, not just something that can be copied directly into the IDE you're using).

To be perfectly honest, if you've been having a tough time with programming in general (including that recent java experience), you shouldn't be copy/pasting anything right now. Type out the examples--especially while they're still relatively small--and make sure you understand, line-by-line, what it is you're doing with each instruction. You're not doing yourself any favors by choosing to shortcut this early.

Is there any way to make it print the line and not close up quickly (other than the pause thingy)? Like is there a default setting that would make the window stay open so that I can actually read the text then close the window myself?

I'm not sure if it works the same way in VS 2008 C++ Express, but in Visual Studio 2005/2008 (the full versions), you don't need to use getline/get at the end of your main function to keep the console window open IFF you are NOT debugging. Use Control-F5 instead of F5 to build and run the program while you're in Visual Studio and it will automatically give you a non-closing console window with a "Press any key to continue . . . " at the end.

The advice people have given obviously works (though I would avoid anything system() this early), but make sure you understand why it works and not just what the end result is. What does "system("pause")" do? What do "cin.getline" and "cin.get" do?

I don't know how to navigate any folders from the command window.

cd directory_name - changes current directory to directory_name

Most Visual Studio projects by default are stored in a Projects directory somewhere within your My Documents folder. Your project, according to the output, is stored in:

c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice

The actual location of the executable you would run is usually in a Debug directory below this:

c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\debug\practice.exe

So, you would open a command window (Start > Run > cmd), and then change your directory to the debug directory by typing:

cd c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\debug\

The prompt changes to indicate your new directory, and then you just run your program:

practice.exe

, and the console window stays open after it's done because it wasn't created specifically for that process.

You can verify the location of your executable by looking at the Output window when you run Debug in Visual Studio. One of the very first lines should be something like:

'Practice.exe': Loaded 'c:\documents and settings\lawrenzo\my documents\visual studio 2008\projects\practice\debug\Practice.exe', Symbols loaded.

Both Visual Studio 2005 and 2008 have console windows that do not close automatically if you are using the proper settings.

I'm pretty sure this is not the case, though I'd love to be wrong. I have never seen a setting that forces the console window to stay open in any version of Visual Studio when in debug.

First anyways with vs 2008 you don't need to have std:: in front of cin or cout.

Actually, you do need to specify the std namespace unless you've utilized "using" earlier; in this case the example doesn't. Even if VS2008 did though, it's not good advice to give without also explaining why you would be able to omit it.

I don't know.. programming is kind of pointless unless you start young and can figure stuff out by yourself.

Anyone who can solve a problem can learn how to program if they are sufficiently motivated and have the resources available (the latter of which, no excuses can be made for given how ubiquitous they are).

[Purrrfect]

Thanks for the Ctrl-F5 point, I like.

[Zosi]

Teorem: In the interests of following your own advice, you should mention that Ctrl-F5 isn't just "insert a magic pause", it's also "run without debugging". The "magic pause" on run in debug was indeed a default behavior of some older versions of VC++, but not 2008.

It also only works when you're running from VS, so you SHOULD learn the very simple system("pause") for situations where you want a pause in the actual program that will execute regardless of whether you're debugging or not.

Devek: If you're going to bash VS for not having an integrated terminal, at least offer a solution that runs on Woozie's platform. Eclipse with CDT has a nice integrated terminal tab, although I really don't think I'd recommend using it simply because you can't deal with external console windows.

Spoiler: show

http://farm4.static.flickr.com/3433/...db827d22_o.jpg

[Vic]

First anyways with vs 2008 you don't need to have std:: in front of cin or cout.

Actually, you do need to specify the std namespace unless you've utilized "using" earlier; in this case the example doesn't. Even if VS2008 did though, it's not good advice to give without also explaining why you would be able to omit it.

Correct; I saw my mistake and fixed it after realizing it heh.

Well to explain namespaces, a namespace is a grouping a global classes, objects, functions, variables, and include files contained within a library. By specifying the std namespace with "using", you gain access to the information within the C++ standard lib.

[Teorem]

Teorem: In the interests of following your own advice, you should mention that Ctrl-F5 isn't just "insert a magic pause", it's also "run without debugging". The "magic pause" on run in debug was indeed a default behavior of some older versions of VC++, but not 2008.

I thought I did in the previous sentence where I mentioned it works when you're not debugging, but you're right, I could and should have made that clearer.

The console preservation on debug isn't in VS2005, though it might have been in 6.0. Not that that really matters anyway since it shouldn't be offered through MSDNAA anymore and no one should really see it in academic environments, much less the workplace (...hopefully.)

It also only works when you're running from VS, so you SHOULD learn the very simple system("pause") for situations where you want a pause in the actual program that will execute regardless of whether you're debugging or not.

There's two reasons why I say it's too early to mention system("pause"):

- It's platform-specific. The call system() may be consistent across platforms for invoking a new shell, but pause is not. If another IDE on another operating system is used--which isn't out of the realm of possibility as development or coursework progresses--it isn't going to work and whoever uses it should understand why (and of course later, how they can get it to work in those environments if they really want/need it).

- It (in my opinion) can be easily misused and promote poor programming practices, particularly when it comes to debugging. If someone is learning how to use Visual Studio, they should learn how to use breakpoints first to stop the program's execution (and be able to use the IDE to read current values, step through loops, etc.). If debugging isn't involved, learn "get" first and then shell invocation calls.

I'm not saying it's invalid or a bad suggestion, but I just don't think it's appropriate this early in the learning process, especially without understanding what it does. There's already a lot of black box just-accept-it-works-because-it-does in the initial learning curve.

Correct; I saw my mistake and fixed it after realizing it heh.

Sorry, it took a while to compose because I was playing around with Visual Studio and didn't notice the edit after I submitted the post.