GCE O/L ICT Lesson 10: Mastering Pascal Programming

Programming is the process of giving instructions to a computer to solve a problem. For GCE O/L ICT students, Lesson 10 introduces Pascal, a high-level language designed to teach structured programming.

This guide bridges the gap between complex logic and functional code using the SchoolICT.net interactive Pascal tool.

1. What is Pascal Programming?

Pascal is a structured, high-level programming language. It is particularly useful for students because its syntax (the rules of the language) is very close to English, making it easier to learn the fundamentals of computer science.

The Programming Process:

1. Problem Analysis: Understanding the requirements.
2. Algorithm Design: Creating a flowchart or pseudocode.
3. Coding: Writing the actual Pascal code.
4. Compiling & Executing: Converting code to machine language and running it.
5. Debugging: Finding and fixing errors.

2. Structure of a Pascal Program

Every Pascal program follows a specific template. If you miss one part, the compiler will return an error.

Program ProgramName; {Header}

Var
  VariableList : DataType; {Declaration}

Begin
  {Instructions go here}
  Writeln('Hello World');
End. {Termination}

3. Data Types and Variables

In Pascal, you must declare what kind of data a variable will hold before you use it.

• Integer: Whole numbers (e.g., 10, -5).
• Real: Numbers with decimals (e.g., 3.14).
• Char: A single character (e.g., ‘A’).
• String: A sequence of characters (e.g., ‘SchoolICT’).
• Boolean: Logical values (True or False).

4. Control Structures

Control structures determine the flow of the program. There are three main types:

A. Sequence

Instructions are executed one after another in a straight line.

B. Selection (Decision Making)

The program chooses a path based on a condition.

• IF-THEN-ELSE:DelphiIf marks >= 50 Then Writeln('Pass') Else Writeln('Fail');

C. Repetition (Looping)

Repeating a block of code multiple times.

• FOR Loop: Used when you know exactly how many times to repeat.
• WHILE Loop: Repeats as long as a condition is true.
• REPEAT-UNTIL: Repeats until a condition becomes true.

5. Basic Input and Output Commands

To interact with the user, Pascal uses:

• Write / Writeln: To display text on the screen. (Writeln moves the cursor to the next line).
• Read / Readln: To get input from the user’s keyboard.

6. Interactive Learning: Pascal Simulator

The biggest challenge in learning programming is not having a compiler ready. At SchoolICT.net, we provide an Online Pascal Simulator designed specifically for O/L students.

How to use the learning tool:

• Code Sandbox: Type your Pascal code directly into the browser.
• Error Highlighting: The tool helps you identify missing semicolons (;) or incorrect keywords.
• Logic Visualization: Run simple programs to see how variables change their values step-by-step.
• Pre-set Examples: Load common O/L exam programs, such as “Find the Area of a Circle” or “Check if a Number is Even or Odd.”

7. Exam Success Tips for Pascal

1. The Semicolon Rule: Almost every line in Pascal ends with a semicolon (;). The only exception is usually the line before an End or Else.
2. The Period at the End: Every Pascal program must end with End. (a period). If you use a semicolon there, the program won’t finish.
3. Variable Assignment: Use := to assign a value to a variable (e.g., Total := A + B;). Using just = is for comparisons only!
4. Dry Running: Practice “Dry Running” your code on paper. Trace the value of each variable line by line to ensure your logic is correct.

Conclusion: Your First Step into Software Engineering

Pascal isn’t just a lesson for an exam; it is the foundation of logical thinking. By mastering the control structures and syntax covered in Lesson 10, you are preparing yourself for modern languages like Python, Java, and C++.

Start your coding journey today:

• 📖 Full GCE O/L Pascal Programming Notes
• 💻 Try the Interactive Pascal Simulator