Teach Yourself Borland C++ in 14 Days - portal

336 Day 9
Adding Functions and Data Members
to Code
As you know by now, C++Builder is a great tool for quickly creating the user interface portion
of a Windows application. It creates event handlers for you so that you can begin entering
code to drive your application. It won’t be long, however, before you find the need to start
adding more complicated code to your applications. That means adding your own data
members and functions to the code that C++Builder generates. For example, a simple
application might contain two dozen event handlers of various types. C++Builder creates all
these event handlers for you; you simply fill in the blanks with working code. In order to make
the application a viable, working application, however, you might have to write another two
dozen functions of your own.
Adding your own functions and data members to C++Builder-generated code is not a
difficult task, but you need to know the rules or you can get into trouble.
How C++Builder Manages Class Declarations
As you know, when you create a new form in the Form Designer, C++Builder creates three
files for you: the form file, the source code unit, and the unit’s header. When C++Builder
creates the class declaration in the header, it essentially creates two sections. The first section
is the part of the class declaration that C++Builder manages. The second section is the part
that you manage. On Day 7 you created the ScratchPad program. If you did the exercises at
the end of that chapter, you also created an About box for the program and added a few more
buttons. Listing 9.1 contains the main form’s header as it appears after adding these
enhancements.
Listing 9.1. SPMain.h.
1: class TScratchPad : public TForm
2: {
3: __published: // IDE-managed Components
4: TPanel *Panel1;
5: TBevel *Bevel1;
6: TSpeedButton *FileOpenBtn;
7: TSpeedButton *FileSaveBtn;
8: TStatusBar *StatusBar;
9: TMainMenu *MainMenu;
10: TMenuItem *FileMenu;
11: TMenuItem *FileOpen;
12: TMenuItem *FileSave;
13: TMenuItem *FileSaveAs;
14: TMenuItem *N1;
15: TMenuItem *FilePrintSetup;
16: TMenuItem *N2;