New operator is used to create a new object of an existing class and associate the object with a variable that names it. Basically new operator instantiates a class by allocating memory for a new object and returning reference to that memory.
Every class needs an object to use its member and methods by other classes. Programmer have to create that object using new operator to use functionality provided by that class. Following is the syntax to create new object of an existing class:
Class_variable =new Class_Name();
This syntax basically describes some points about new operator as below:
- Allocates memory to class_variable for new object of class.
- It invokes object constructor.
- Requires only single postfix argument which calls to constructor.
- Returns reference to memory which is usually assigned to variable of appropriate type.
Following statement will create an object of city class and allocate memory to this newly created object:
City metro;
metro = new City();
The equivalent code for the above statement that can be written in single line is:
City metro = new City();
So new operator does two things overall i.e. it first allocates memory somewhere to hold an instance of the type, and then calls a constructor to initialize an instance of the type in that newly allocated memory.
After creating new object for a class, that object can use all the members and methods defined in that class. You can assign all the properties for that class and operate available or new functions on those properties.