Computing Society: Session 2 Programming Basics

Posted on 2025-01-24 Edited on 2025-02-13 In code

Session 2: Variables, Data Types, Control Structures, and Basic Operations

Total Time: 60 minutes

2.1 Understanding Variables and Data Types (15 minutes)

Explanation:

🔹 Variables store data that can be reused throughout a program. In Python, they’re dynamically typed, while C++ requires explicit typing.
🔸 Data Types determine what kind of data a variable holds:

📊 Integers (int): Whole numbers.
🔢 Floats (float): Numbers with decimals.
📝 Strings (str): Text enclosed in quotes.
✅ Booleans (bool): True/False values.

Activity Breakdown:

(5 minutes) Introduction to variables in Python and C++.
- Noobs Task: Assign values to variables and print them.
  - Example: age = 16 in Python; int age = 16; in C++.
(5 minutes) Overview of common data types.
- Noobs Task: Print different types of variables.
  - Example: num1 = 5 (int), pi = 3.14 (float), name = "Alex" (string), is_student = True (bool).
(5 minutes)
- Challenging Task 🏆: Design a data structure to store the information of a competition. The competition should have teams, team members, and scores. Use dictionaries in Python or structs in C++.
  - Example: In Python, use a dictionary where team names are keys, and values are lists of tuples with member names and scores.
  - In C++, use structs and a map.

2.2 Basic Arithmetic and Logical Operations (10 minutes)

Explanation:

➕ Arithmetic Operations: Perform basic math on numbers using +, -, *, /, %.
✅ Logical Operations: Compare values using and, or, and not.
💡 XOR (exclusive OR): Returns true if exactly one condition is true, but not both.

Activity Breakdown:

(5 minutes) Arithmetic operations.
- Noobs Task: Perform basic arithmetic operations like addition and subtraction.
  - Example: result = 10 + 5 (Python) or int result = 10 + 5; (C++).
(5 minutes) Logical operations.
- Noobs Task: Write a program that uses and, or, not to compare boolean values.
  - Example: is_even = (num % 2 == 0) and is_positive = (num > 0).
Challenging Task 🏆: Achieve XOR using only and, or, and not.

2.3 Control Structures: Loops and Conditionals (20 minutes)

Explanation:

⚙️ Conditionals: Let the program decide what code to run based on conditions using if, else, elif in Python, or if, else if, else in C++.
🔁 Loops: Repeat code using for and while loops. A for loop repeats a fixed number of times, while a while loop repeats as long as a condition is true.

Activity Breakdown:

(10 minutes) Conditionals.
- Noobs Task: Create a program that categorizes a number (grade) using if-else.
  - Example: Check if a score is >=90 (A), >=80 (B), etc.
(10 minutes) Loops.
- Noobs Task: Write a program that prints numbers from 1 to 10 using for and while.
  - Example: for i in range(1, 11): print(i) in Python.
Challenging Task 🏆: Write a program that checks if any character in a given string appears twice using two loops.
- Additional Challenge 💡: Can you optimize it to O(n) time complexity?

2.4 Hands-On Practice: Simple Calculations and Control Flow (15 minutes)

Explanation:

Now, students apply their knowledge by building simple programs that combine all the above concepts.

Activity Breakdown:

(10 minutes) Simple calculator or number guessing game.
- Noobs Task: Create a basic calculator that asks for two numbers and an operation (+, -, *, /), then performs the calculation.
(5 minutes)
- Challenging Task 🏆: Use a single int to check if a character in a string appears twice, achieving O(n) time complexity using bit manipulation (数位压缩).
  - Tip 💡: Use bitwise operations to track character occurrences.

Wrap-Up and Q&A (5 minutes)

Summarize the session with a quick review of key concepts 📚.
Open the floor for questions and additional clarifications 🙋‍♂️.