DEV Community: Aliza Kanwal

Abstraction in C++ - Explained in Simple Words

Aliza Kanwal — Thu, 12 Nov 2026 14:36:24 +0000

Abstraction means showing only the important things and hiding the complex details.

Think of a car. When you drive a car, you only see steering, brake, and accelerator. You don't see how the engine works inside. You don't need to know it. You just drive. This is Abstraction!

In C++, we use Abstraction to make our code simple to use.

Let's see a simple example:


cpp
#include <iostream>
using namespace std;

class Car {
public:
    void start() {
        cout << "Car Started!" << endl;
        startEngine();
    }

private:
    void startEngine() {
        cout << "Engine is working inside..." << endl;
    }
};

int main() {
    Car myCar;
    myCar.start();
    return 0;
}
Output:
Car Started!
Engine is working inside...

Encapsulation in C++ - Explained in Simple Words

Aliza Kanwal — Thu, 12 Nov 2026 14:33:55 +0000

Encapsulation means hiding your data to keep it safe. In C++, we make data private and we only allow access through public functions.

Think of it like a bank locker. Your money is inside the locker (private). You cannot touch it directly. You have to use a key (public function) to open it. This keeps your money safe.

Let's see a simple example:


cpp
#include <iostream>
using namespace std;

class BankAccount {
private:
    int balance = 1000;

public:
    void showBalance() {
        cout << "Your balance is: " << balance << endl;
    }

    void deposit(int amount) {
        balance = balance + amount;
        cout << "Deposited: " << amount << endl;
    }
};

int main() {
    BankAccount myAccount;
    myAccount.showBalance();
    myAccount.deposit(500);
    myAccount.showBalance();
    return 0;
}
Your balance is: 1000
Deposited: 500
Your balance is: 1500

Polymorphism in C++ - Explained in Simple Words

Aliza Kanwal — Thu, 12 Nov 2026 14:30:45 +0000

Polymorphism means "many forms". In C++, it means one function name can work in many different ways.

Think of it like this: Every animal makes a sound, but the sound is different.
Cat says Meow, Dog says Bark, Bird says Chirp. The function name is same - makeSound() - but the result is different. This is Polymorphism!

Let's see a simple example:


cpp
#include <iostream>
using namespace std;

class Animal {
public:
    virtual void makeSound() {
        cout << "Animal makes a sound" << endl;
    }
};

class Cat : public Animal {
public:
    void makeSound() override {
        cout << "Meow!" << endl;
    }
};

class Dog : public Animal {
public:
    void makeSound() override {
        cout << "Bark!" << endl;
    }
};

int main() {
    Animal* a1 = new Cat();
    Animal* a2 = new Dog();

    a1->makeSound();
    a2->makeSound();
    return 0;
}
Output:
Meow!
Bark!

What is Inheritance in OOP? Explained in Simple Words

Aliza Kanwal — Thu, 12 Nov 2026 14:23:00 +0000

Inheritance means ek Class ko doosri Class ki cheezain mil jati hain.

Jaise bachay ko apne Maa Baap se cheezain milti hain, waise hi Child Class ko Parent Class se properties milti hain.

Example: Person ek Parent Class hai. Student ek Child Class hai. Student ko Person ki har cheez milegi, plus uski apni bhi hogi.


cpp
#include<iostream>
using namespace std;

// Parent Class
class Person {
public:
    string name;
    int age;

    void introduce() {
        cout << "My name is " << name << endl;
        cout << "My age is " << age << endl;
    }
};

// Child Class - Person se Inheritance le rahi hai
class Student : public Person {
public:
    int rollNo;

    void showRollNo() {
        cout << "My Roll No is " << rollNo << endl;
    }
};

int main() {
    Student s1;
    s1.name = "Aliza";
    s1.age = 20;
    s1.rollNo = 1;

    s1.introduce();
    s1.showRollNo();

    return 0;
}
Output:
My name is Aliza
My age is 20
My Roll No is 1

What is Class and Object in OOP? Explained in Simple Words

Aliza Kanwal — Thu, 12 Nov 2026 14:08:54 +0000

Class is a blueprint. Object is a real thing made from that blueprint.

Example: Agar Class "Car ka Naksha" hai, to Object us nakshay se bani hui asli Car hai.

Ek Class se hum jitne marzi Objects bana sakte hain, jaise neeche code me s1 aur s2 banaye hain.


cpp
#include <iostream>
using namespace std;

class Student {
public:
    string name;
    int rollNo;

    void introduce() {
        cout << "My name is " << name << endl;
        cout << "My Roll No is " << rollNo << endl;
    }
};

int main() {
    Student s1;
    s1.name = "Aliza";
    s1.rollNo = 1;
    s1.introduce();

    Student s2;
    s2.name = "Ayesha";
    s2.rollNo = 2;
    s2.introduce();

    return 0;
}