Constructors in C++ - Cyborg Coding

In C++, a constructor is a special member function that is automatically called when an object of a class is created. The constructor is used to initialize the properties of the object and set the initial state of the object. Constructors are typically defined with the same name as the class and have no return type.

A class can have multiple constructors, each with a different set of parameters. This is known as constructor overloading. The constructor that is called depends on the arguments passed when the object is created.

For example:

class MyClass {

private:

    int x;

    int y;

public:

    MyClass() {

        x = 0;

        y = 0;

    }

    MyClass(int xVal, int yVal) {

        x = xVal;

        y = yVal;

    }

    int getX() { return x; }

    int getY() { return y; }

};

In this example, "MyClass" has two constructors: a default constructor with no parameters, and a constructor that takes two parameters, "xVal" and "yVal".

The default constructor is automatically called when an object is created without any arguments:

MyClass myObject;

This creates an object of the "MyClass" class, and the default constructor is called, initializing the properties "x" and "y" to 0.

The constructor with parameters is called when an object is created with arguments:

MyClass myObject(10,20);

This creates an object of the "MyClass" class, and the constructor with parameters is called, initializing the properties "x" and "y" to 10 and 20 respectively.

It is also important to note that if a class does not define any constructors, the compiler will automatically provide a default constructor. This default constructor will not have any parameters, and it will not do any initialization. Also, if a class defines at least one constructor, the compiler will not provide a default constructor.

In summary, constructors in C++ are special member functions that are automatically called when an object of a class is created. They are used to initialize the properties of the object and set the initial state of the object. A class can have multiple constructors, each with a different set of parameters, this is known as constructor overloading. The default constructor is automatically provided by the compiler if no constructor is defined. If a class defines at least one constructor, the compiler will not provide a default constructor.