A constructor refers to a special method used to initialize a new instance of a specific class. Since it is a method, a constructor includes a set of associated statements created to perform a general function. Constructors are part of a class; therefore, they interact with variables to carry out their tasks.
In most programming languages, a constructor for a certain class must have the same name as the class. This rule is implemented to ensure that the system knows all the classes and their corresponding constructors, and that errors will not be encountered during the execution of the source codes.
In certain languages, if the user does not create a constructor for a particular class, the system would automatically create one for it. This type of constructor is public and does not accept any parameters. Its main purpose is to call the classes that the current class inherits from, which are also called base classes.
Multiple constructors may be included in a class. In the event of a class having two or more constructors, these constructors will have the same name. The class will be able to distinguish one constructor from the other through its arguments. This is because all constructors handle unique arguments. Still, there are constructors which do not take any arguments. These are aptly called non-argument constructors.
Constructors are incorporated in many programming languages. JAVA and C# are two of the most common languages that use constructors in their source codes.