Introduction To Object Oriented Programming

Build a Motor Bike Class

• adjust speed and gears.

We would want to create a few objects and play with them

• Understand concepts of Class, Object, State, Behavior
• Understand basics of Encapsulation and Abstraction

Procedural/Structured Programming

• Thinking in terms of procedures/methods/functions

    //Global Data

    fly() {       
      travelToAirport();
      findCheckInCounter();
      checkIn();
      passSecurityCheck();
      waitForBoardingCall();
      boardTheFlight();
      wishTheAirHostess();
      takeOff();
      haveFun();
      landing();
    }

Object Oriented Programming

• Thinking about Objects
  • Class, Object
    • Data (state)
    • Actions (behaviour)

Aeroplane

• airline, make, type, position //data
• takeoff(), land(), cruise() //actions

AirHostess

• name, address //data
• wish(), serve() //actions

Passenger

• name, address //data
• takeCab(), checkin(), walk(), smile() //actions

Object Oriented Terminology

class Planet {
     name, location, distanceFromSun //data/state/fields
         revolve(), rotate()     //actions/behavior/methods
}

Planet earth = new Planet();
Planet venus = new Planet();

Terminology

• Class - Template ex : Planet, Person
• Objects/Instances - ex : earth, venus, mahatmaGandhi, nelsonMandela
• Member Data/State/Fields - Data present in each object - name, location, distanceFromSun
• Actions/Methods/Behaviour - What actions can be performed on each object?

Exercises

Online Shopping System

• Customer
  • name, address
  • login(), logout(), selectProduct(product)
• Shopping Cart
  • items
  • add(item), remove(item)
• Product
  • name, price, quantityAvailable
  • order(), changePrice()

Person

• name, address, hobbies, work
• walk(), run(), sleep(), eat(), drink()