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Overload, Override and Static
1. Difference Between Overloading and Overriding
| Aspect | Overloading | Overriding |
|---|---|---|
| Definition | Same function name with different parameter lists | Redefining a virtual function in a derived class |
| Inheritance required | ❌ No | ✅ Yes |
| Parameters | Must be different | Must be the same |
| Return type | Can differ (with rules) | Must be the same or covariant |
| Binding | Compile-time (static binding) | Run-time (dynamic binding) |
| Keyword needed | ❌ No | virtual (base), override (derived, recommended) |
| Polymorphism | Compile-time polymorphism | Run-time polymorphism |
2. How to Implement Overloading and Overriding
(A) Function Overloading (Compile-Time Polymorphism)
class Math {public: int add(int a, int b) { return a + b; }
double add(double a, double b) { return a + b; }};📌 Same function name, different parameter types.
(B) Function Overriding (Run-Time Polymorphism)
class Base {public: virtual void show() { cout << "Base show" << endl; }};
class Derived : public Base {public: void show() override { cout << "Derived show" << endl; }};Base* obj = new Derived();obj->show(); // Output: Derived show📌 Requires:
- Inheritance
virtualfunction in base class- Same function signature
3. Purpose of Using Static Data
A static data member belongs to the class itself, not to individual objects.
Why Use Static Data?
- Shared among all objects of the class
- Maintains common state
- Saves memory (only one copy exists)
- Useful for counting objects
- Represents class-level information
Example
class Counter {public: static int count; Counter() { count++; }};
int Counter::count = 0;Counter a, b, c;cout << Counter::count; // Output: 3One-Line Exam Summary
- Overloading: Same function name, different parameters (compile-time).
- Overriding: Redefining a virtual function in a derived class (run-time).
- Static data: Shared class-level data used by all objects.
Overload, Override and Static
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