Classes & Objects

Overview

A Class is a blueprint or template. An Object is an actual instance created from that blueprint. Classes define what an object will look like and how it will behave.

Syntax

cpp

// Class definition
class Player {
public:
    int health = 100; // Attribute
    
    void heal() {     // Method
        health += 10;
    }
};

int main() {
    // Creating an object (Instance)
    Player p1; 
    
    // Using the object
    p1.heal(); 
    return 0;
}

Common Pitfalls

Forgetting the semicolon `;` at the end of the class closing brace `}`. This is a very common compiler error for beginners.

Interview Tips

Understand the difference between a class (the architectural blueprint) and an object (the actual house built from the blueprint).

Real-World Example

Creating multiple independent objects from one class.

example

cpp

#include <iostream>
using namespace std;

class Dog {
public:
    string name;
    
    void bark() {
        cout << name << " says Woof!" << endl;
    }
};

int main() {
    Dog dog1;
    dog1.name = "Rex";
    
    Dog dog2;
    dog2.name = "Buddy";
    
    dog1.bark(); // Rex says Woof!
    dog2.bark(); // Buddy says Woof!
    return 0;
}

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