6 - Variable Scope

Dive into 6 - Variable Scope 🧠

🎯 Knowing Where Variables Live

Scope determines where a variable can be used in your code. In Java, curly braces { } create a new scope.

---

🧍‍♂️ Method and Class Scope

Variables declared outside of methods belong to the whole robot class and can be used anywhere inside it.

public class MyBot extends Robot {
    private int moveCount = 0;  // class scope
 
    public void run() {
        moveCount++;  // accessible here
    }
}

moveCount is available in every method of the class.

---

📦 Block Scope

Variables declared inside a method or block only exist there.

public void run() {
    int scans = 0;  // method scope
 
    if (getEnergy() > 50) {
        double power = 2;  // block scope
        fire(power);
    }
 
    // power is no longer accessible here
}

power disappears once the if block ends.

---

🔁 Loop Scope

Variables declared in a loop header or body stay inside the loop.

for (int i = 0; i < 3; i++) {
    double angle = i * 45;
    turnRight(angle);
}
 
// i and angle are out of scope here

Use loop variables when you only need them during iteration.

---

✅ Why Scope Matters

• Prevents name conflicts
• Frees memory when variables go out of scope
• Keeps code organized and predictable

---

Navigation

⬅️ Back: Reactionary Logic ➡️ Next: Day 7