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00 Inbox/29605321 - OOP 4_16.md

@@ -52,9 +52,6 @@ class Pokemon {
 public: // visibility modifier
 	int exp;
 	int level;
-	int attack;
-	int defense;
-	int speed;
 	int hp;
 
 	void upgrade(int gainedExp) {
@@ -67,10 +64,97 @@ public: // visibility modifier
 }
 
 int main() {
-	Pokemon fukano = {3600, 1, 400, 400, 20, 1200};
+	Pokemon fukano = {3600, 1, 1200};
 	cout << "Exp of fukano: " << fukano.exp << endl;
 	fukano.upgrade(400);
 	cout << "Exp of fukano: " << fukano.exp << endl;
 }
 ```
 
+### Scope Modifiers
+If we want to hide data beyond the class itself we can use the `private` visibility modifier:
+
+```C++
+class Pokemon {
+public:
+	string name;
+	
+private: 
+	int exp;
+	int level;
+	int hp;
+
+public:
+	void upgrade(int gainedExp) {
+		exp += gainedExp;
+		if (exp >= 4000) {
+			exp -= 4000;
+			level += 1;	
+		}
+	}
+}
+
+int main() {
+	Pokemon fukano = {3600, 1, 1200};
+	fukano.upgrade(400); // this is OK
+	fukano.exp += 400; // this is not OK
+}
+``` 
+
+### Getters and Setters
+_Getters and Setters_ allow **controlling the change** like:
+- ensuring a number is in a range
+- update depending parameters (like level with exp)
+
+```c++
+class Pokemon {
+// ...
+public:
+	void setExp() { /*...*/ }
+	int getExp() { /*...*/ }
+}
+```
+
+### Constructors
+
+Given the class:
+```C++
+class Pokemon {
+private:
+	int exp;
+	int level;
+}
+```
+
+We can create a new instance using the _basic constructor_:
+```C++
+class Pokemon {
+// ...
+public: 
+	// Default constructor: allows Pokemon <name>; -> exp = 0, level = 0;
+	Pokemon(): exp(0), level(0) {}; 
+	// or
+	Pokemon(0, 0);
+
+	// Base constructor
+	Pokemon(int e, int l) {
+		exp = e;
+		level = l;		
+	}
+	// or as
+	Pokemon(int e, int l): exp(e), level(l) {};
+}
+
+int main() {
+	Pokemon fukano(3600, 1);
+}
+```
+
+We can also create an instance as a copy of another object of the _same class_:
+```C++
+class Pokemon {
+// ...
+public:
+	Pokemon(const Pokemon& p)
+}
+```