What is a Variable?
Think of a variable as a box that stores data. It's used to store things like player health, score, name, etc. in games.
Variable Types
Integer (int)
- Description: Can only store whole numbers (no decimal points)
- Example:
int hp = 100;(health 100) - Use cases: Health, score, level, count, etc.
Float
- Description: Stores numbers with decimal points
- Example:
float pi = 3.14f;(must add 'f') - Use cases: Speed, distance, ratio, etc.
String
- Description: Stores text
- Example:
string myName = "John";(quotes required) - Use cases: Name, message, description, etc.
Boolean (bool)
- Description: Stores only true or false
- Example:
bool isGameOver = false; - Use cases: Game over status, button activation, etc.
Access Modifiers
private
- Description: Can only be used within this script
- Example:
private int hp = 100; - When to use: When other scripts don't need to access it
public
- Description: Visible and editable in Unity Inspector window
- Example:
public int hp = 100; - When to use: When you want to change values in Inspector during gameplay
Unity Lifecycle Methods
Start()
- When executed: Runs only once when the game starts
- Purpose: Initial setup, variable initialization
- Example: Set health to 100, display start message
Update()
- When executed: Runs continuously every frame (about 60 times per second)
- Purpose: Things that need continuous checking
- Example: Key input detection, collision checking
Conditional Statements (if)
Conditional statements express "if ~ then".
if (hp <= 0)
{
Debug.Log("Game Over!");
}
- Behavior: If hp is 0 or less, output "Game Over!" message
- Usage: Game over when health reaches 0, level up when score exceeds 100, etc.
Arithmetic Operations
Operations to add or subtract numbers from variables.
hp = hp - 100; // Subtract 100 from hp
hp = hp + 50; // Add 50 to hp
hp = hp * 2; // Multiply hp by 2
hp = hp / 2; // Divide hp by 2
Debug.Log
A tool to check if code is running correctly.
Debug.Log("Hello!");
Debug.Log("Current health: " + hp);
- You can check messages in the Console window at the bottom of Unity
- Useful for checking variable values or finding errors