Branching Logic & Decisions

Learning Objectives

• Write boolean expressions and use comparison operators (==, !=, <, <=, >, >=).
• Control program flow with if, elif, and else.
• Combine conditions with logical operators (and, or, not) and understand truthiness.
• Apply guard clauses (e.g., prevent division by zero) and provide simple user feedback.

Session Plan (theory)

1. Recap (Week 1–2) Printing & formatting; input() and basic casting.
2. Conditionals in Python
   • if / elif / else structure and execution order.
   • Comparison & logical operators; grouping with parentheses.
   • Truthy/falsey values and common patterns (guard clauses, early returns with exit() for scripts).
3. Pattern examples
   • Range checks, multi-branch decisions, simple validation messages.

Hands-on

• Console Calculator v2 (conditionals)
  • Read two numbers (float) and an operator from the user.
  • Use an if/elif/else chain to perform +, -, *, /.
  • Guard against division by zero and unknown operators.
  • Print a clear, formatted result line.