Pseudocode Guide for IGCSE Paper 2

Introduction to Pseudocode

• Importance in IGCSE Paper 2, fundamental for coding logic.
• Focus on logic efficiency rather than syntax.
• Understanding the rules of pseudocode.

Why Learn Pseudocode?

• A universal language for all codes.
• Prepares for various programming languages, which evolve over time.
• Focus on logic rather than specific syntax of programming languages like Python.

Components of Pseudocode

1. Font Style and Size

• Presented in monospace font.
• Consistency is key, similar to writing in a specific format.

2. Indentation

• Important for segmenting code.
• Lines are indented by four spaces for segments, two spaces for continuation lines.

3. Case and Italics

• Keywords in uppercase (e.g., IF, REPEAT).
• Identifiers in mixed case (e.g., numberOfPlayers).
• Meta variables are less common but indicate conditions in brackets.

4. Lines and Numbering

• Code runs line by line, sequence is critical.

5. Comments

• Use // to add explanations in code, not required but useful.

Variables, Constants, and Data Types

• Atomic Type Names: Integer, Real, Char, String, Boolean.
• Literals: Examples of each type, e.g., 21 (Integer), "Hello" (String).
• Identifiers: Could be variables, constants, procedures, functions.
  • Variables follow rules such as starting with a letter, not a number.

Arrays

• 1D and 2D Arrays: Structures of elements accessible by indexes.
• Used for lists; declare with type and bounds.

Operations

Input and Output

• Keywords: INPUT, OUTPUT.
• Can use READ and PRINT interchangeably.

Arithmetic Operations

• Basic operations: Addition, Subtraction, Multiplication, Division.
• Special operators: MOD, DIV.

Logic Operators

• Keywords: AND, OR, NOT.
• Used in conditions.

Control Structures

1. If Statements

• Used for conditional execution.
• Nested if statements for complex conditions.

2. Case Statements

• When multiple conditions can match a variable value.
• Use of CASE and OTHERWISE.

3. Loops

• For Loop: Fixed repetition, FOR keyword.
• Repeat Until Loop: Executes until condition is met, always runs at least once.
• While Loop: Executes based on condition, may not run if condition isn't met.

Conclusion

• Practice pseudocode through questions and real scenarios.
• Emphasis on logic understanding over syntax in IGCSE.
• Next steps involve practicing with pseudocode questions to enhance skills.