Building Applications in CodeWarrior Pro 8

by Jen Golbeck, Winter 2001

revised by Mike Hasak, Winter 2003

In CodeWarrior, code is managed as a "project". A project is a collection of C++ files that will be combined into producing one executable as follows:

To build a new standard application

1. Launch CodeWarrior. The icon is located on the hard drive in Programming:CodeWarrior Pro 7:Metrowerks CodeWarrior and is called CodeWarrior IDE 4.2

2. When CodeWarrior launches, all you will see is the set of pull down menus at the top. A default page or application will not show up. To write a program you will need to create a project. This holds the files, the executable, the debugger, and other necessary information. To do this, go to the file menu and select "new..."

3. You will be prompted to create a project. In the window on the left, select Mac OS C++ Stationery. On the right, type in the name of your project. This will create a folder containing all the data in the location selected in the “Location:” field. You should make sure to either create this folder on a disk of yours or to make a copy of it and take it with you. The hard drives are wiped clean every night in the maclab, and there is no way to recover code that you wrote and did not take with you.

4. You will then be prompted to select the type of project. Choose Mac OS Carbon then Standard Console then C++ Console Carbon.

5. CodeWarrior will create a project, and will open a window that contains all of the project information. You should be primarily concerned with the sources folder under the "Files" tab. This shows what files are going to be compiled as part of your program. By default, a "Hello World" program will be there. You can view this code by double clicking on the name of the file.

This file is often a good starting place, something to use as a template. However, you may want to start with your own code from scratch.

The carb.r file is part of the Carbon stationery (code that tells Codewarrior how to compile for the Mac OS) – don’t throw it away, but you can safely ignore it.

6. To start with your own code, the most important thing is to first remove the HelloWorld.cp file from the project. Since any C++ program can have only one main function, you want to remove this default file so your code will execute properly. To do this, simply click on the file name in the project window, and drag it into the desktop trash. A shadow of the file outline will follow your mouse to the trash.

7. To create a new file from scratch, go to the file menu and select "New Text File". This will create a blank file that you edit in the CodeWarrior simple text editor.

8. Having entered your code, you will want to save it. You should save this file in the folder created for your project. You chose this location when you created the project in step 3. Once your file is saved, it is still not included in the project. You will need to add it to the project window. The simplest way is to drag the file from its folder on the desktop into the project window. When your mouse enters the project window, a black line will appear indicating into which folder the file will be dropped. Move your mouse so that the line is immediately under the sources folder. Then drop the file there. Now, when you look in the sources folder in the project window, your file should appear there. Alternately, you can go to the project pull-down menu and select Add Files. Select your new file, and click Add.

In either case, you will be able to view it by simply double clicking on its name in the project window.

You may also take code that you have written in other plain text editors and add them to your CodeWarrior project in the same manner.

9. You may add as many files to the project as you like, but remember that a project only can contain one application. That means only one file can contain a main function. If you want to create separate programs, you need separate CodeWarrior Projects.

10. To compile your application and to check the syntax there are two options. Make () will check syntax and create an application. Run () will do everything Make does, plus launch the created application. To do either of there, go to the project menu and choose "Make" "Run" (or hit apple-M or apple-R respectively on the keyboard). CodeWarrior will start to build the project by first checking the syntax, and pointing out any errors. If all of the code is correct, it will create an application for you and, if you have chosen Run, launch that application. Note that all of your files will be automatically saved when you compile an application.

11. If there are errors, you will be given a window that lists the expected error, as well as the line and file in which it occurs.

There are two categories of problems: errors and warnings. Errors are syntactic errors that must be corrected for the code to compile. Warnings are things that CodeWarrior things might be wrong, but which will not prevent the code from compiling.

The window above shows several things to keep in mind. The actual error in the code is that there is a semicolon missingfrom the end of the line

cout << "Hello World, this is CodeWarrior!" << endl

However, the debugger points out that the error is on the next line. The lesson is this: debuggers and syntax checkers aren't perfect. CodeWarrior cannot fix your code for you (nor can our tutors). You should think of the syntax checker as a tool to help you find errors, not as something that should be correct in pointing out every error of your code. Additionally, you may sometimes see hundreds of errors appear. Often there is one syntax error that makes it impossible for CodeWarrior to understand the rest of your code. It is to your benefit to fix one error at a time and then re-compile. In many cases, fixing the first error eliminates many others as well.

Debugging is without a doubt the most frustrating process in coding. This is a tool to help , not to do that work for you.

You may correct errors in the lower section of the Errors and Warnings window. This will automatically change them in the file. A red arrow points to the line where CodeWarrior things the error occurs, and the text is highlighted. If you have multiple errors, clicking on the next error brings up the file and location of that error in the lower window.

12 . Once you have successfully compiled your code, it can be run. This launches a separate application that contains your working code. You may switch back and forth between that application and your code in CodeWarrior, however if you want to recompile your code, you must first quit the running application.

Using the Debugger

The debugger in CodeWarrior allows you to move step by step through your program to see which function calls are being executed, what each state is of member variables, and how loops and single lines are being executed.

1. If you go back to the project menu, you'll see that above the "Run" option is "Debug". Select that, or use the apple-R keystroke indicated in the menu, or use the green-bug button in the project window ().

3. After checking for syntax errors, the debugger window will appear.

The buttons across the top provide you with your options. From left to right they are

* "Play" which will execute your code until it reaches a stopping point (see step 4)

* "Stop" which stops execution

* "Kill" which kills the program and brings you back to the project window

* "Step Over", which executes a line and moves to the next line (not showing you the internals of any functions that are called)

* "Step Into" which executes the current line, and shows you step by step any sub-functions being executed. Try this to see how involved this whole libraries business is.

* "Step Out" which brings the debugger up one level in the execution of sub-functions or phrases.

In the source window is a blue arrow pointing to the line about to be executed. You may move that arrow to any line at any time to re-execute a statement, or to skip to a specific section of code. The Variables window on the top right shows any variables and their current value. The stack window shows functions being executed.

4. Stopping points are markers that tell the debugger to stop executing if you have clicked on Play. If you have isolated a section of your code which you think may have problems, you can set a marker there to indicate that all the code before it should be executed, and when you reach this point, execution in the debugger should stop and you should be able to step through it with the Step buttons defined above.

By clicking on the grey field to the left of your code in the code editor, a red dot will show up. To remove a red dot, click on it again. You may set as many or as few stopping points you like – the line adjacent to a red dot will be denoted as a stopping point.

This is a stopping point. Simply click next to the line you want to stop at, and then run the debugger.

Other Features of CodeWarrior

As you may have noticed, CodeWarrior provides some nice features like color-coding. There are many, but a few in particular will make coding much easier.

Across the top of the code editor window are five buttons; the first three are particularly useful. The last two control syntax coloring schemes and versions. Of the others, from left to right...

Header Files - This button lists all of the header files included in your project. It's a big list because of all the default system headers. If you click on this button, you can see the list and select a header. That header will then open in a new window. This is useful if you have included your own headers and want to open one for reference or correction.

Functions - This button lists all of the functions in the current file. You can use it to select a function and jump to that part of the code. In long files, this is a great time saver. Note that it will not jump to function prototypes, only function definitions.

Markers - This button allows you to set or view markers. It is very similar to the Functions button in that it will jump you to a specific place in the code. However, you can place a marker anywhere in the code you like, and give it any name you want. This is useful if you have several classes in one file, if you have prototypes and then definitions, or of there is a piece of a long function that you keep coming back to.