Constructors & Destructors

* Constructors and destructors are special member functions that are used for initializing and cleaning up objects, respectively, in object-oriented programming (OOP).

Constructors

A constructor is a special member function with the same name as the class. It is automatically called when an object of the class is created. The purpose of a constructor is to initialize the object's state.

• Default Constructor:

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

• Parameterized Constructor:

class MyClass {
public:
    // Parameterized constructor
    MyClass(int x, int y) {
        // Initialization code using parameters
    }
};

• Copy Constructor:

class MyClass {
public:
    // Copy constructor
    MyClass(const MyClass& other) {
        // Copy the state of 'other' object
    }
};

Destructors

A destructor is a special member function with the same name as the class, preceded by a tilde ('~'). It is automatically called when an object goes out of scope or is explicitly deleted. The purpose of a destructor is to release resources and clean up.

class MyClass {
public:
    // Destructor
    ~MyClass() {
        // Cleanup code goes here
    }
};

⤏ Now, let's create a simple program to see how contractors & contractors work in C++.

#include＜iostream＞

class MyObject {
private:
    int data;

public:
    // Default constructor
    MyObject() {
        std::cout << "Default constructor called" << std::endl;
        data = 0;
    }

    // Parameterized constructor
    MyObject(int value) {
        std::cout << "Parameterized constructor called" << std::endl;
        data = value;
    }

    // Destructor
    ~MyObject() {
        std::cout << "Destructor called for data: " << data << std::endl;
    }
};

int main() {
    // Using constructors
    MyObject obj1;          // Default constructor
    MyObject obj2(42);       // Parameterized constructor

    // Destructor is automatically called when objects go out of scope
    // Destructor called for obj2, then obj1
    return 0;
                   
}

Default constructor called      
Parameterized constructor called
Destructor called for data: 42  
Destructor called for data: 0  

In the example above, the constructors are used to initialize objects, and the destructor is automatically called when the objects go out of scope at the end of the main function.

* Constructors initialize objects in C++, while destructors clean up resources when objects go out of scope. Pay attention to warning-free coding practices, such as using member initialization lists and ensuring proper initialization order.