pjhayward's Pascal Tutorial
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Lesson One - Sample Program
Lesson Two - Program Structure
Lesson Three - Data Types
Lesson Four - Variables
Lesson Five - Text I/O
Lesson Six - Subroutines
Lesson Seven - Conditional
Lesson Eight - Arrays
Lesson Nine - Loops
Lesson Ten - Units
|Lesson Two - Program Structure|
You already have a little experience with the Pascal program structure. Now I'll go into some additional detail. Each program has a set structure. A template, if you will, of the program structure, goes like this:
program PROGRAMNAME; const // Constant Declarations type // Type Declarations var // Variable Declarations //Subroutine Declarations begin // main program declaration end.
A declaration is basically just a statement; For example:
This "declares" that the constant named FirstLetter is equal to lowercase 'a'. Type and Variable declarations can be a bit more complicated, but all declarations follow the same basic principle. You are outlining for the compiler what some part of the program is, or what it is equal to.
The template above is not a legitimate pascal program. If you don't have any constants, types, or variables to declare, you should leave out the corresponding section. So, the above template, minus the unused sections, would give the following (working) program:
program PROGRAMNAME; begin end.Obviously, this program doesn't actually DO anything. It just starts up, then exits. But it illustrates the most basic building block you need for a working program. Next