Lecture Notes: Teaching Carol to Turn Right

Introduction

• Carol the robot cannot naturally turn right.
• In the "Make a Tower" exercise, a situation arises where Carol needs to turn right.

Standard Commands for Carol

• Carol originally knows only four commands.
• Turning right is not one of them.
• Alternative method:
  • Turn left three times to simulate a right turn.

Introducing Functions

• Functions allow us to teach Carol new commands beyond the original four.
• Terminology:
  • Functions may be called procedures, tasks, or processes.
  • In this context, we're focusing on functions.

Creating a Turn Right Function

• Defining a Function in Python
  • Use def followed by the function name and parentheses.
  • End the definition line with a colon.
  • Indent commands in the function body.
  • Example to turn right using three left turns: def turn_right(): turn_left() turn_left() turn_left()

Importance of Function Order in Python

• Functions must be defined before they are called in the code.
• Python reads code from top to bottom.
• Calling an undefined function results in an error.

Example Walkthrough: Making Carol Turn Right

• Initial Steps
  • Use commands like move, put_ball, etc.
  • Adjust Carol's direction using turn commands.
• Implementing Turn Right
  • Attempting to use turn_right without definition results in an error.
  • Substitute three turn_left commands to proceed.
• Defining the Turn Right Function
  • Place function definition at the top of the code.
  • Ensure correct indentation for function body and other code segments.
  • Avoid errors by ensuring all parts of the function are correctly indented.
• Executing the Defined Function
  • Code skips the function definition when executed until the function is called.
  • Call turn_right() to execute the new command.

Conclusion

• Successfully taught Carol a new command to turn right using functions.
• Encouragement to experiment with code in the editor.