Explain Runtime polymorphism with an example.
SOLUTION....
Runtime Polymorphism (Dynamic Polymorphism) in C++
Definition:
Runtime polymorphism lets a call made through a base-class pointer/reference invoke the overridden function of the derived object at runtime. In C++, this is achieved with virtual functions.
How it works (in short):
Mark a base-class function as
virtual.Override it in derived classes with the same signature (use
override).Call through a base pointer/reference; the actual function chosen depends on the dynamic type of the object (late binding).
Make destructors virtual in polymorphic bases to avoid resource leaks.
Why use it:
Provides a single interface (base class) for multiple behaviors (derived classes), enabling extensible, clean designs.
#include <iostream> using namespace std; class Shape { public: virtual double area() const = 0; // pure virtual => abstract base virtual ~Shape() = default; // always virtual in polymorphic base }; class Rectangle : public Shape { double w, h; public: Rectangle(double W, double H) : w(W), h(H) {} double area() const override { return w * h; } }; class Triangle : public Shape { double b, h; public: Triangle(double B, double H) : b(B), h(H) {} double area() const override { return 0.5 * b * h; } }; int main() { Shape* s; // base-class pointer Rectangle r(10, 5); Triangle t(6, 4); s = &r; // points to Rectangle cout << "Rectangle area: " << s->area() << '\n'; s = &t; // points to Triangle cout << "Triangle area: " << s->area() << '\n'; return 0; }
OUTPUT
