feat : added polymorphism

0xNILADRI · 0xNILADRI · commit 97f3dda26725 · 2021-06-14T21:09:04.000+05:30
diff --git a/12.Polymorphism/1_function_overriding.cpp b/12.Polymorphism/1_function_overriding.cpp
@@ -0,0 +1,27 @@
+#include<iostream>
+using namespace std;
+
+class Parent{
+    public:
+        void display(){
+            cout<<"display of base"<<endl;
+        }
+};
+
+class Child:public Parent{
+    public:
+        void display(){
+            cout<<"display of child"<<endl;
+        }
+};
+
+int main(){
+    Parent p;
+    p.display(); // parent display function
+
+    Child c;
+    c.display(); // child display fucntion
+    c.Parent::display(); // calling parent display class using scope operator
+
+    return 0;
+}
diff --git a/12.Polymorphism/2_virtual_fucntion.cpp b/12.Polymorphism/2_virtual_fucntion.cpp
@@ -0,0 +1,22 @@
+#include <iostream>
+using namespace std;
+
+class Parent{
+    public:
+        virtual void func(){
+            cout<<"function of parent"<<endl;
+        }
+};
+
+class Child:public Parent{
+    public:
+        void func(){
+            cout<<"function of child"<<endl;
+        }
+};
+
+int main(){
+    Parent *ptr = new Child();
+    ptr->func(); // normally without the virtual keyword fucntion of Parent class would have been called because of the pointer.
+    return 0;
+}
diff --git a/12.Polymorphism/3_polymorphism.cpp b/12.Polymorphism/3_polymorphism.cpp
@@ -0,0 +1,64 @@
+/*
+    Polymorphism must have three things :
+        * A generalized class with a pointer pointing to the object of a child class.
+            (this helps in dynamic programming and achieving less memory usage)
+        
+        * Function overriding in both the generalized as well as the child classes.
+
+        * Virtual keyword must be used in order to locate the function call to its own object class.
+
+
+    There are three types of Base class :
+        * All concrete functions.
+            purpose : reusablity.
+        
+        * Some concrete and some pure vitual functions.    // Abstract Class
+            purpose : reusablity and polymorphism
+
+        * All pure virtual functions.                      // Abstract Class : Interface
+            purpose : polymorphism.
+
+*/
+
+#include <iostream>
+using namespace std;
+
+// generalized / abstract class : no object can be created.
+class Car{
+    public:
+        // pure virtual class, since assigned to 0. If not called it becomes abstract.
+        virtual void start() = 0;
+        virtual void stop() = 0;
+};
+
+class Innova:public Car{
+    public:
+        void start(){
+            cout<<"Innova started."<<endl;
+        }
+        void stop(){
+            cout<<"Innova stopped."<<endl;
+        }
+};
+
+class Swift:public Car{
+    public:
+        void start(){
+            cout<<"Swift started."<<endl;
+        }
+        void stop(){
+            cout<<"Swift stopped."<<endl;
+        }
+};
+
+int main(){
+    Car *car = new Innova();
+    car->start();
+    car->stop();
+
+    car = new Swift();
+    car->start();
+    car->stop();
+
+    return 0;
+}
diff --git a/12.Polymorphism/4_practice_student_exercise.cpp b/12.Polymorphism/4_practice_student_exercise.cpp
@@ -0,0 +1,59 @@
+#include <iostream>
+using namespace std;
+
+class Shape{
+    public:
+        virtual float area()=0;
+        virtual float perimeter()=0;
+};
+
+class Rectangle:public Shape{
+    private:
+        float length;
+        float breadth;
+    public:
+        // constructor 
+        Rectangle(float length = 1, float breadth = 1){
+            this->length = length;
+            this->breadth = breadth;
+        }
+
+        float area(){
+            return length*breadth;
+        }
+
+        float perimeter(){
+            return 2 * (length+breadth);
+        }
+};
+
+class Circle:public Shape{
+    private:
+        float radius;
+    public:
+        // constructor 
+        Circle(float radius = 1){
+            this->radius = radius;
+        }
+
+        float area(){
+            return 3.14*radius*radius;
+        }
+
+        float perimeter(){
+            return 2*3.14*radius;
+        }
+};
+
+int main(){
+    Shape *s;
+    s = new Rectangle(1.2,4);
+    cout<<"Area of rectangle "<<s->area()<<endl;
+    cout<<"Perimeter of rectangle "<<s->perimeter()<<endl;
+    cout<<endl;
+    s = new Circle(4.2);
+    cout<<"Area of circle "<<s->area()<<endl;
+    cout<<"Circumference of circle "<<s->perimeter()<<endl;
+    
+    return 0;
+}
