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C++ with OOP : CONSTRUCTORS & DESTRUCTORS


Constructors and destructors are essential components of object-oriented programming (OOP) in C++. Constructors are special member functions that are automatically called when an object of a class is created, while destructors are called when an object goes out of scope or is explicitly deleted. Let's discuss each of them in detail:

Constructors:

Constructors are used to initialize objects of a class. They have the same name as the class and are invoked automatically when an object of the class is created. Constructors can have parameters, which allow for initialization of object data members during object creation.

Default Constructor:

A default constructor is a constructor that takes no arguments.

class MyClass {
public:
    // Default constructor
    MyClass() {
        // Initialization code
    }
};

 

Parameterized Constructor:

A parameterized constructor is a constructor with parameters, used to initialize data members with specific values during object creation.

class MyClass {
private:
    int value;
public:
    // Parameterized constructor
    MyClass(int v) {
        value = v;
    }
};

Copy Constructor:

A copy constructor is a constructor which creates an object by initializing it with an object of the same class.

class MyClass {
private:
    int value;
public:
    // Copy constructor
    MyClass(const MyClass& other) {
        value = other.value;
    }
};

Destructors:

Destructors are special member functions that are called automatically when an object goes out of scope or is explicitly deleted using the delete operator. Destructors are typically used to release resources acquired by the object during its lifetime, such as memory allocated dynamically.

class MyClass {
public:
    // Constructor
    MyClass() {
        // Initialization code
    }

    // Destructor
    ~MyClass() {
        // Clean-up code
    }
};

Destructors have the same name as the class prefixed with a tilde (~). They do not take any parameters and do not return any value.

Example:

#include <iostream>

class Rectangle {
private:
    int width;
    int height;

public:
    // Parameterized constructor
    Rectangle(int w, int h) : width(w), height(h) {
        std::cout << "Constructor invoked. Width: " << width << ",
Height: " << height << std::endl;
    }

    // Destructor
    ~Rectangle() {
        std::cout << "Destructor invoked. Width: " << width << ",
Height: " << height << std::endl;
    }
};

int main() {
    Rectangle rect1(5, 10); // Constructor invoked
    {
        Rectangle rect2(3, 6); // Constructor invoked
    } // Destructor invoked for rect2
    Rectangle rect3(7, 14); // Constructor invoked
    return 0;
} // Destructor invoked for rect1 and rect3


In this example, you can see how constructors are invoked when objects of the Rectangle class are created and how destructors are invoked when these objects go out of scope.

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