[Class Report] Introduction to System Development – Week 6: Let’s Create Your Own Commands with Functions!

In the 6th week of our programming fundamentals class, the theme was “Functions”. We learned how to write and use functions as a way to organize everything we’ve studied so far—variables, conditionals, loops, and lists.

■ Today’s Introduction: “Functions = Creating Your Own Commands”

Mr. Tanaka: “Haven’t you written the same code over and over again? You can make it cleaner by turning it into a function.”

He showed the following example on the whiteboard:

def say_hello():
    print("Hello!")

say_hello()
say_hello()

Mr. Tanaka: “This defines a function called ‘say_hello’ that prints ‘Hello!’ when called. You can use it as many times as you want.”

Student A: “Wait, we can create our own commands?”
Student B: “That’s super useful!”

■ Exercise 1: Let’s Make a Basic Function!

The first task was to create a function that displays your favorite message.

def greet():
    print("Welcome to the world of programming!")

greet()

Student C: “So we add () when we call it?”
Mr. Tanaka: “Exactly! That’s the signal to ‘run’ the function.”

■ Exercise 2: Trying Functions with Arguments!

Next, we learned how to pass information to a function using arguments.

def greet(name):
    print(name + ", hello!")

greet("Yamada")
greet("Suzuki")

Mr. Tanaka: “This name is like a container that receives the passed data.”

Student D: “It’s like talking to the function!”
Student E: “Feels like making a game dialogue.”

■ Quiet Time: Let’s Make Your Own Function!

The assignment: “Create your own original function and use it at least twice.”
Students began freely creating functions using everything they’ve learned so far.

💡 Examples of Student Ideas

• A function combining name and greeting
• A function that calculates and returns results (like total scores)
• A function that displays quotes from their favorite characters

Student F: “It’s seriously nice not having to write the same thing three times.”
Mr. Tanaka: “That’s what we call ‘reusability’!”

■ Teacher’s Message

“Functions are like tools you make to put in your toolbox. Once you’ve made them, you can use them again and again. It’s an important concept to keep your code clean and easy to understand.”

■ Next Week’s Preview: A Mini Project Where Functions Call Each Other!

Next time, we’ll try a mini project where we combine multiple functions to create a simple interactive app or diagnostic tool.
It’ll be a week where students can truly feel the excitement of “assembling and running” their own parts.

First-year students have been steadily building their ability to “create” step by step. Their code is starting to show “meaning” and “structure”, and now they’re entering the world of actual project creation.