What can be changed when overloading methods or operators?

Overloading allows you to change:

• Parameter list: number, order, or types of parameters.
• Return type: can differ (for methods). For operators, the return type determines the operation semantics.
• Access modifiers: can vary.

You cannot change:

• Only the return type (without changing the parameter list).
• Only the access modifiers (without changing the parameter list).

Example of method overloading in Java:

class Calculator {
    // Overloading method add: int + int
    public int add(int a, int b) {
        return a + b;
    }

    // Overloading method add: double + double
    public double add(double a, double b) {
        return a + b;
    }

    // Overloading method add: int + int + int
    public int add(int a, int b, int c) {
        return a + b + c;
    }
}

Example of overloading the "+" operator in C++ for a user-defined class:

class Vector {
public:
    int x, y;

    Vector(int x = 0, int y = 0) : x(x), y(y) {}

    // Overloading the + operator
    Vector operator+(const Vector& other) const {
        return Vector(x + other.x, y + other.y);
    }
};

Comparison table of the original and overloaded method (example):

Aspect	Original method add(int a, int b)	Overloaded method add(double a, double b)
Method name	add	add
Parameters	int a, int b	double a, double b
Quantity	2	2
Types	int, int	double, double
Return type	int	double
Modifier	public	public