CodeJackpot - CPP Constructors

CPP Constructors

C++ is an object-oriented programming language that allows developers to create classes and objects. Constructors are an essential part of C++ classes, as they are responsible for initializing the objects of a class. In this article, we will discuss the basics of C++ constructors, their types, and how to use them in your code.

What are Constructors?

A constructor is a special member function of a class that is called automatically when an object of that class is created. The primary purpose of a constructor is to initialize the data members of the class. Constructors have the same name as the class and do not have a return type, not even void.

Constructors are called automatically when an object is created, and they can be used to set default values for the data members of the class. Constructors can also be used to allocate memory for the object and to perform any other initialization tasks that are required.

Types of Constructors

There are three types of constructors in C++:

Default Constructor
Parameterized Constructor
Copy Constructor

Default Constructor

A default constructor is a constructor that takes no arguments. It is called automatically when an object is created without any arguments. If a class does not have a default constructor, the compiler will generate one automatically.

Here is an example of a default constructor:


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

Parameterized Constructor

A parameterized constructor is a constructor that takes one or more arguments. It is used to initialize the data members of the class with the values passed as arguments. A class can have multiple parameterized constructors with different argument lists.

Here is an example of a parameterized constructor:


class MyClass {
public:
  MyClass(int x, int y) {
    // constructor code here
  }
};

Copy Constructor

A copy constructor is a constructor that takes an object of the same class as an argument. It is used to create a new object that is a copy of the existing object. The copy constructor is called automatically when an object is created as a copy of another object.

Here is an example of a copy constructor:


class MyClass {
public:
  MyClass(const MyClass& obj) {
    // constructor code here
  }
};

Using Constructors in Your Code

To use constructors in your code, you need to create an object of the class. When you create an object, the constructor is called automatically. Here is an example:


MyClass obj; // default constructor called
MyClass obj2(10, 20); // parameterized constructor called
MyClass obj3 = obj2; // copy constructor called

In the above example, we created three objects of the MyClass class. The first object was created using the default constructor, the second object was created using the parameterized constructor, and the third object was created as a copy of the second object using the copy constructor.

Conclusion

Constructors are an essential part of C++ classes, as they are responsible for initializing the objects of a class. There are three types of constructors in C++: default constructors, parameterized constructors, and copy constructors. By using constructors in your code, you can create objects of a class and initialize their data members with default or custom values.

C++