Static and Final members

lesson#19.3 - Static and Final members/main.d

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+import std.stdio: writeln;
+
+class Data { 
+	float x, y, width, height;
+	int damage;
+
+	// final functions cannot be overriden by a sublcass
+	final float getRegenerationRate() {
+		return damage*0.8f;
+	}
+}
+
+class Enemy: Data {
+	Data data;
+	static int num;
+
+	this() {
+		writeln(num++);
+	}
+
+	~this() {
+		writeln(--num);
+	}
+
+	static bool isColliding(/*Data data1, Data data2*/) {
+		// collision logic
+		return true;
+	}
+
+	//override float getRegenerationRate() {} // error!
+}
+
+void main() {
+	Enemy e1 = new Enemy();
+	Enemy e2 = new Enemy();
+	Enemy e3 = new Enemy();
+	
+	// static members can be accessed directly by the class name without creating an instance of that class
+	writeln("Number of enemies: ", Enemy.num, ".");
+	writeln("Enemies colliding: ", Enemy.isColliding(/* any data of the same type*/));
+}