Computer Programming II SS2 Digital Technologies Lesson Note

In our last lesson, we learned how to plan a program using Algorithms and Flowcharts. Now, it’s time to actually “speak” to the computer.

Since a computer doesn’t understand English directly (it only understands electricity—1s and 0s), we use a Programming Language like Python. It acts as a translator. You write something that looks like English, and Python converts it into something the computer can execute.

Why Python?

• It is very easy to read.
• It is used by big companies like Google, NASA, and Netflix.
• You don’t need to be a math genius to start!

Your First Line of Code: The print() Function

The most basic thing a computer can do is talk back to you. In Python, we use the print() command.

Example: print(“Hello, SS2 Students!”)

Note: Anything inside the quotation marks “” is called a String. It tells the computer: “Just display this text exactly as it is; don’t try to calculate it!”

Variables: The “Storage Boxes”

Imagine you are moving house. You put your books in a box and write “BOOKS” on the outside. Later, when you need them, you just look for the box labeled “BOOKS.”

In programming, a Variable is a box in the computer’s memory where we store data. We give the box a name so we can find it later.

How to create a variable: user_name = “Chidi” age = 16

• user_name is the label on the box.
• “Chidi” is the item inside the box.

Data Types: What’s in the Box?

Not everything we store is the same. Python needs to know what kind of data is in the box so it knows how to handle it.

Basic Operators: Doing Math

Computers are basically giant calculators. Python uses symbols to perform math on our variables:

• + (Addition): 5 + 2 is 7
• – (Subtraction): 5 – 2 is 3
• * (Multiplication): 5 * 2 is 10
• / (Division): 10 / 2 is 5.0
• == (Comparison): Is x equal to y?

Important: In programming, one equals sign (=) is used to assign a value to a box. Two equals signs (==) are used to check if two things are the same.

Input: Asking the User

A good program isn’t just a one-way street. You want to ask the user for information. We use the input() command.

Example: name = input(“What is your name? “) print(“Welcome to the class, ” + name)

Summary Checklist

• Python is our translator.
• Variables are boxes that hold information.
• Strings are for text; Integers are for numbers.
• print() shows output; input() gets information.

Class Lab Activity

1. Open the Python IDLE (the program where we type code).
2. Task 1: Write a program that prints your name and your favorite food.
3. Task 2: Create two variables, num1 and num2. Give them values like 10 and 20. Create a third variable called result that adds them together and prints it.
4. Task 3 (Challenge): Write a program that asks for a student’s name and their age, then prints: “Hello [Name], you will be [Age + 1] next year!”