7.1 Algorithm design and problem-solving

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Flowchart Symbols

1. Standard Flowchart Symbols

Using the correct shapes is essential for exam marks. Each shape represents a specific type of instruction.

Shape Name Function
START / STOP
Terminator Used at the very beginning and the end of every flowchart.
X ← A + B
Process Used for calculations or assigning values to variables.
INPUT / OUTPUT
Input / Output Used when the program gets data from a user or displays a result.
Decision Used for Selection (IF statements). Has two exit paths: Yes and No.
PRE-DEFINED
Pre-defined Process Used for Subroutines or Functions defined elsewhere.

2. Example Algorithm: Pass/Fail Checker

Let's represent an algorithm that asks for a student's mark and tells them if they passed (Pass mark = 50).

START
INPUT Mark
Mark ≥ 50?
YES
OUTPUT "Pass"
NO
OUTPUT "Fail"
STOP

3. Drawing Rules

  • Flowcharts should generally flow from top to bottom or left to right.
  • Arrowheads must be used on all lines to show the direction of flow.
  • Decision symbols must have exactly two output lines, clearly labeled (e.g., True/False or Yes/No).
⚠️ Exam Warning: Do not confuse the Process (Rectangle) with the Input/Output (Parallelogram). Marks are frequently lost for using a rectangle when asking for a user's name!