Explore OOP in C++ to write cleaner, modular, and scalable code. Learn classes in C++, data hiding, encapsulation, abstraction, inheritance, and polymorphism in C++.

Become  a C++ Programmer

This module aims to teach us how to write cleaner, more modular, and scalable code in C++ by providing an understanding of OOP in C++. We'll start with the basics of object-oriented programming and build up to advanced concepts such as inheritance, data hiding, and polymorphism. Along the way, we'll explore how each concept applies to C++ and how various C++ features facilitate OOP.

Object-Oriented Programming in C++

What is the output of the following piece of code?

```C++
#include <iostream>
using namespace std;

class Base{
public:
 virtual void print() { 
 cout <<" Base Print";
 }
};
 
class Derived: public Base{
public:
 void print() {
 cout <<"Derived Print" ; 
 }
};
 
int main(){
 Base * bp;
 		Derived obj;
 
 bp = &obj;
 bp->print();
}
```

What is the output of the following piece of code?
<pre><code class="language-C++">#include &lt;iostream&gt;
using namespace std;

class Base{
public:
 virtual void print() { 
 cout &lt;&lt;&quot; Base Print&quot;;
 }
};
 
class Derived: public Base{
public:
 void print() {
 cout &lt;&lt;&quot;Derived Print&quot; ; 
 }
};
 
int main(){
 Base * bp;
 		Derived obj;
 
 bp = &amp;obj;
 bp-&gt;print();
}
</code></pre>

Does the code run successfully?

```C++
#include<iostream>
using namespace std;
 
class Base{
public:
 virtual void show() = 0;
};
 
int main(){
 Base b;
 Base *bp;
}
```

Does the code run successfully?
<pre><code class="language-C++">#include&lt;iostream&gt;
using namespace std;
 
class Base{
public:
 virtual void show() = 0;
};
 
int main(){
 Base b;
 Base *bp;
}
</code></pre>

What does the following piece of code do?

```C++
#include <iostream>
using namespace std;

class Shape {
 public:
 virtual float getArea() = 0;
};

class Rectangle : public Shape { 
 private:
 float width;
 float height;

 public:
 Rectangle(float wid, float heigh) {
 width = wid;
 height = heigh;
 }
 float getArea(){
 return width * height; 
 }
};

int main() {
	Shape * shp = new Rectangle(4, 5);
 float num = shp->getArea();
 cout << "Area of rectangle is " << num << endl;
}
```

What does the following piece of code do?
<pre><code class="language-C++">#include &lt;iostream&gt;
using namespace std;

class Shape {
 public:
 virtual float getArea() = 0;
};

class Rectangle : public Shape { 
 private:
 float width;
 float height;

 public:
 Rectangle(float wid, float heigh) {
 width = wid;
 height = heigh;
 }
 float getArea(){
 return width * height; 
 }
};

int main() {
	Shape * shp = new Rectangle(4, 5);
 float num = shp-&gt;getArea();
 cout &lt;&lt; &quot;Area of rectangle is &quot; &lt;&lt; num &lt;&lt; endl;
}
</code></pre>

Let's test your understanding of the polymorphism.

Introduction

Classes

Data Hiding

Inheritance

Polymorphism

Conclusion

Quiz