Question

Explain with an example interface and implementation.

Answer 1

Interface Vs Implementation:

An interface is a set of actions that an object can do. For example, when you press a light switch, the light goes on, you may not have cared how it splashed the light. In an Object-Oriented Programming language, an Interface is a description of all functions that a class must have in order to be a new interface.

In our example, anything that “ACTS LIKE” a light, should have function definitions like turn on ( ) and a turn off ( ). The purpose of interfaces is to allow the computer to enforce the properties of the class of TYPE T (whatever the interface is) must have functions called X, Y, Z, etc.

A class declaration combines the external interface (its local state) with an implementation of that interface (the code that carries out the behaviour). An object is an instance created from the class. The interface defines an object’s visibility to the outside world.

Characteristics of interface

• The class template specifies the interfaces to enable an object to be created and operated properly.
• An object’s attributes and behavior are controlled by sending functions to the object.

Interface	Implementation
The interface defines what an object can do, but won’t actually do it	Implementation carries out the instructions defined in the interface

Example:

• The person who drives the car doesn’t care about the internal working.
• To increase the speed of the car he just presses the accelerator to get the desired behaviour.
• Here the accelerator is the interface between the driver (the calling / invoking object) and the engine (the called object).
• In this case, the function call would be Speed (70): This is the interface.
• Internally, the engine of the car is doing all the things.
• It’s where fuel, air, pressure, and electricity come together to create the power to move the vehicle.
  All of these actions are separated from the driver, who just wants to go faster. Thus we separate interface from implementation.