Computer Class: Flowcharts and Algorithms

Introduction

• Focus on learning how to think like a programmer.
• Topics covered:
  • Flowcharts
  • Algorithms
  • Pseudocode
• Importance of planning before coding.

Courses and Resources

• Available courses: Physics, Chemistry, Biology, Maths for CBSE & ICSE classes 8-10.
• Coding courses available in Python and Java.
• Cambridge IGCSE Physics and Chemistry courses.
• Online presence: YouTube, Facebook, Instagram.

Coding Recipe Analogy

• Coding is likened to cooking recipes.
• Steps must be followed in order.
• Mistakes in steps lead to incorrect outcomes.

Code Recipes

• Code Recipe: The plan or logic of a program.
• Expressed in different styles:
  • Flowchart: Visual representation.
  • Algorithm: Step-by-step written instructions.
  • Pseudocode: Rough code, informal writing.

Flowcharts

• Definition: Pictorial representation of a problem's solution.
• Symbols used:
  • Oval: Start/Stop.
  • Parallelogram: Input/Output.
  • Rectangle: Processing.
  • Diamond: Decision making (Yes/No).
  • Circle: Connector.
• Benefits: Easy to read and understand logic.

Algorithms

• Definition: Set of steps to solve a problem.
• Features:
  • Written in simple English.
  • Steps must be clearly numbered.
  • Focus on the logic, not programming syntax.

Pseudocode

• Definition: Informal way to describe program steps without strict syntax.
• Advantages:
  • Quick to write down.
  • Focuses on logic rather than syntax.

Example Problem: Area of a Circle

• Goal: Write code to find the area of a circle.
• Considerations:
  • Input: Radius of the circle.
  • Formula: Area = πr² (π typically 3.14).

Flowchart Example

• Start → Input radius → Calculate area (πr²) → Output area → Stop

Algorithm Example

• Start
• Input radius r
• Area = 3.14 * r * r
• Print area
• Stop

Pseudocode Example

• Input radius in variable r
• Area = 3.14 * r * r
• Display area

Example Problem: Find Smaller of Two Numbers

Flowchart

• Start → Input A, B → Decision: Is A < B?
  • Yes → Print A → Stop
  • No → Print B → Stop

Algorithm

• Start
• Input A, B
• If A < B then Print A, else Print B
• Stop

Pseudocode

• Input two numbers in variables A, B
• If A < B then Print A else Print B

Example Problem: Factorial of a Number

• Factorial: Product of all numbers up to a given number.

Flowchart

• Start → Input n
• Initialize i=1, f=1
• Loop: f = f * i, increment i
• Condition: i > n?
  • Yes: Print f, Stop
  • No: Loop

Algorithm

• Start
• Input n
• Initialize i=1, f=1
• While i ≤ n, repeat:
  • f = f * i
  • i = i + 1
• Print f
• Stop

Pseudocode

• Input number in n
• i = 1, f = 1
• While i ≤ n: f = f * i, i = i + 1
• Display f

Conclusion

• Importance of planning before coding.
• Verification through dry runs and trace tables.
• Choose the method that suits your style: Flowchart, Algorithm, or Pseudocode.
• Encouragement to practice and apply these techniques.