Getters / Setters

Getters and Setters are public methods that provide controlled access to private data members.

Getter → reads a private variable. Setter → writes/modifies a private variable.

Why Not Just Make Members Public?

// BAD — public member, no control
class Player { public: int health; };
Player p; p.health = -9999; // invalid! no validation

// GOOD — private with getter/setter
class Player {
private: int health;
public:
    void setHealth(int h) {
        if (h < 0) h = 0;
        if (h > 100) h = 100;
        health = h;
    }
    int getHealth() { return health; }
};

Basic Example

class Person {
private:
    string name; int age;
public:
    string getName() { return name; }
    int getAge() { return age; }
    void setName(string n) { if (!n.empty()) name = n; }
    void setAge(int a) { if (a >= 0 && a <= 150) age = a; }
};

Read Only — Getter Only

class Circle {
private:
    const double radius;
    double area;
public:
    Circle(double r) : radius(r) { area = 3.14 * r * r; }
    double getRadius() { return radius; } // getter only — read only
    double getArea() { return area; }     // getter only — read only
};

Write Only — Setter Only

class SecureLogin {
private:
    string password;
public:
    void setPassword(string p) { // setter only
        if (p.length() >= 8) password = p;
    }
    // no getter — password can never be read directly
};

Getter Returning Reference — Dangerous!

int& getValueRef() { return value; } // dangerous!
d.getValueRef() = 999; // bypasses encapsulation!
// Always return by VALUE in getters unless you have specific reason

Const Getter — Best Practice

int getWidth() const { return width; }   // const getter
int getHeight() const { return height; } // const getter
// Mark getters as const — they don't modify the object
// const objects can only call const methods

Chaining Setters — Fluent Interface

class Builder {
    string name; int age; string city;
public:
    Builder& setName(string n) { name = n; return *this; }
    Builder& setAge(int a) { age = a; return *this; }
    Builder& setCity(string c) { city = c; return *this; }
};

Builder b;
b.setName("Alice").setAge(25).setCity("Delhi").show();

Lazy Initialization in Getter

string getData() const {
    if (!loaded) {
        data = "loaded from file"; // load only when needed
        loaded = true;
    }
    return data;
}

Summary Table

Type	Getter	Setter
Purpose	Read private data	Write private data
Returns	Value	void (usually)
Keyword	const recommended	none
Validation	Not needed	Add here

Key Points

Point	Detail
Always mark getter	const
Validation goes	In setter
Return by	Value (not reference)
Chaining	Return *this from setter
Lazy init	Can be done in getter

One-liner: "Getters and setters provide controlled access to private members — getters read data and should be const, setters write data and should validate input."