Polymorphsim

Polymorphsim: many forms

Two types of polymorphsim

• Compile Time Polymorphsim / Static Binding / Early Binding
  • Function overloading
  • Operator overloading
• Runtime Polymorphsim / Dynamic Binding / Lazy Binding
  • Function overriding (using virtual functions)

Compile Time Polymorphsim

Function overloading

#include <iostream>
using namespace std;

class Test {
public:
  void func(int x) {cout << "Integer" << endl; }
  void func(double x) {cout << "Double" << endl; }
};

int main() {
  Test t1;
  t1.fun(10);
  t1.fun(10.5);
  return 0;
}

output

Integer
Double

Operator overloading

#include <iostream>
using namespace std;

class Complex {
public:
  Complex() = default;
  Complex(int r, int i) : real(r), imag(i) {}
  Complex operator+(Complex const &obj) {
    Complex res;
    res.real = real + obj.real;
    res.imag = imag + obj.imag;
    return res;
  }
  void show() { cout << real << "+" << imag << "i" << endl; }

private:
  int real, imag;
};

int main() {
  Complex c1(1, 3), c2(2, 5);
  Complex c3 = c1 + c2;
  c3.show();
  return 0;
}

output

3+8i

Runtime Polymorphsim

When override keyword is used, compiler checks if the member function in the derived class matches the signature of any virtual function in the base class.

#include <iostream>
using namespace std;

class Base {
public:
  virtual void fun() { cout << "Base" << endl; }
};

class Derived : public Base {
public:
  void fun() override { cout << "Derived" << endl; }
};

int main() {
  Base *a = new Derived();
  a->fun();

  Derived b;
  Base &c = b;
  c.fun();
  return 0;
}

output

Derived
Derived

From

Polymorphism In C++ | Static & Dynamic Binding | Lazy & Early Binding In C++ - YouTube