C173 Webinar 8 Lecture Notes

Introduction

• Picking up from Unit 4.2 on Functions
• Previously covered Units 2 and 3 on fundamental programming constructs using flow charts and pseudocode
• Transitioning from sequential main programs to modular code using functions

Unit 4: Functions

• Purpose: Organize code modularly
• Functions allow transfer of control between the main program and other functions
• Functions can be called by other functions (multi-level)

Unit 4.2: Return Values

• Functions can return values, useful for the output part of the IPO (Input, Process, Output) paradigm
• Return value: Result handed back to the calling function or program
• Return Variable: Must declare within the function

Flowcharts vs. Pseudocode

• Flowcharts require listing variables/parameters outside of the main diagram
• Pseudocode integrates parameters and return variables within the code itself

Participation Activity 4.2.4

• Example: Main function calling a user-defined function height_feet_inches_to_centimeters
• Parameters: User inputs (e.g., feet, inches) transferred to function parameters
• Local Variables: Temporary, exist only within the function
• Return Variable: Provides output back to the main function

Functions Calling Functions

• Main function can call a custom function which in turn calls another function
• Traceability of input parameters through nested function calls

Example: Pizza Calories Calculation

• Main collects user input and calls pizza_calories
• pizza_calories calls circle_area
• Parameters passed down through each level
• Return values propagate back up the call chain

Participation Activity 4.3.3

• Without Functions: Large main program with sequential logic
• With Functions: Smaller main program, functions for specific computations
• Modular code is more readable, facilitates testing and maintenance

Modular Programming Benefits

• Dry Principles (Do Not Repeat Yourself): Avoid code redundancy
• Easier to maintain, fix bugs, and add features

Participation Activity 4.3.5

• Incremental Development: Write, test, and revise small parts of code
• Function Stubs: Placeholder functions to outline structure without full implementation

Key Takeaways

• Modular Development: Divide programs into separate, testable modules
• Incremental Development: Frequent testing of small code segments
• Function Stubs: Capture high-level behavior before low-level details
• Avoid Redundancy: Use functions to prevent repeated code

Conclusion

• Continue exploring unit 4 in future webinars
• Emphasis on understanding modular and structured programming for long-term maintainability and reliability
• Encouragement to reach out for further clarifications and topics for future discussions

Next Steps

• Review Unit 4 material for deeper understanding
• Practice creating and working with functions and modular code
• Prepare for next webinar continuation on Unit 4 after holidays

Wishing everyone a happy holiday season and encouraging ongoing communication for support and feedback.