STRUCTURED PROGRAMMING

2. Program development design

Design tools help programmers visualize the logic of a solution before coding.

Definition: A step-by-step procedure or set of rules to be followed in calculations or other problem-solving operations.
Characteristics:
- Finite: Must end after a specific number of steps.
- Definite: Each step must be clear and unambiguous.
- Effective: Steps must be basic enough to be carried out.

Definition: A diagrammatic representation of an algorithm using standard symbols connected by arrows to show the flow of control.
Common Symbols:
- Oval (Terminal): Start or Stop.
- Parallelogram (Input/Output): Reading data or printing results.
- Rectangle (Process): Calculations or assignments (e.g., x = a + b).
- Diamond (Decision): A condition with Yes/No branches (e.g., Is x > 10?).
- Arrows: Indicate the direction of flow.

Definition: A high-level description of an algorithm that uses structural conventions of programming languages but is intended for human reading rather than machine reading.
Style: It looks like code (using indentation and keywords like IF, WHILE, PRINT) but ignores strict syntax rules (like semicolons).

Example:

Plaintext

START
  READ age
  IF age >= 18 THEN
    PRINT "Eligible to vote"
  ELSE
    PRINT "Not eligible"
  ENDIF
STOP

The process of breaking a complex problem into smaller, manageable sub-problems (modules).
You start with the main goal and break it down level by level until you reach simple tasks that can be easily coded.

Writing code in separate, independent blocks (modules/functions) rather than one massive file.
Advantages:
- Reusability: A module (e.g., a "CalculateTax" function) can be used in different parts of the program.
- Easier Debugging: You can test one module at a time.
- Teamwork: Different programmers can work on different modules simultaneously.