![Pre-Requisite Check
1. Write a simple function to add all numbers in the array below
int [] array = new int[] {2,4,5,6,7,8,8,9,0,10,5,7}
Hint
<visibility> <return type> <name>(<parameters>)
{
<function code>
}
You can logon Here -> C# Online Compiler | .NET Fiddle (dotnetfiddle.net) and complete your
code.](https://image.slidesharecdn.com/introductiontooopsamuelansong-230302134428-75aa2d31/85/Object-Oriented-Programming-OOP-Introduction-3-320.jpg)
![Example Code Snippet
using System;
namespace MyApplication
{
class Program
{
static void Main(string[] args)
{
// Create a myCar object
Car myCar = new Car();
// Call the honk() method (From the Vehicle class) on the myCar object
myCar.honk();
// Display the value of the brand field (from the Vehicle class) and the value of the modelName from the Car class
Console.WriteLine(myCar.brand + " " + myCar.modelName);
}
}
}](https://image.slidesharecdn.com/introductiontooopsamuelansong-230302134428-75aa2d31/85/Object-Oriented-Programming-OOP-Introduction-33-320.jpg)
Object Oriented Programming (OOP) Introduction
- 1. Introduction to OOP Concepts BY: SAMUEL ANSONG
- 2. Pre-Requisites • Familiarity with functions and types • Basic understanding of a class • Has an overall Introduction to programming • We will be using C# for code samples
- 3. Pre-Requisite Check 1. Write a simple function to add all numbers in the array below int [] array = new int[] {2,4,5,6,7,8,8,9,0,10,5,7} Hint <visibility> <return type> <name>(<parameters>) { <function code> } You can logon Here -> C# Online Compiler | .NET Fiddle (dotnetfiddle.net) and complete your code.
- 4. Answer and Modification 1. Overload the function to take 3 numbers 2. Overload the method to take any amount of numbers 3. Change the function into a lambda format
- 5. Structure Procedural Oriented Programming Overview Limitations of POP Object Oriented Programming Overview • Encapsulation • Inheritance • Polymorphism • Abstraction Core Components • Access Modifiers • Static Class and Methods Key Terms
- 6. Procedural Oriented Programming • C , Pascal, FORTRAN, and similar languages are procedural languages • Each Statement in the language tells the computer to do something • Get some Input • Add these numbers • Divide by 4 • Display the number A program in a procedural language is a list of instructions
- 7. Divided Into Functions • Procedural program is divided into functions • Each function has clearly defined purpose and how it interfaces with other functions in the program • One can also further extend functions by grouping several functions together into a larger entity called Modules .
- 8. Divided Into Functions • In Multi-Function program important data items are placed as Global so that they maybe accessed by all functions • Each function may also have its own local data
- 9. Limitations for POP • Since all functions have accessed to the Global Variable , new functions accidentally created can corrupt the data • We can access the data of one function from other since there is no protection • In a large program it is difficult to trace what data is used by which function • If new data is added , all the functions are to be modified to access this data
- 10. Object Oriented Programming • OOP was introduced to overcome flaws in the procedural approach to programming • Such as lack of Reusability and Maintainability • The Fundamental idea behind OOP is to combine into a single unit both data and functions that operate on them. • Such a unit is called an Object .
- 11. Objects? In the real world, just about anything can be seen as an object: car, dog, person, department, city, etc. These have state and behavior. For example, a dog's state is its color, breed and name; its behavior is the way it barks, runs or wags its tail. Objects in OOP are quite similar
- 12. Example Identify the Properties (State) and Behavior (Methods) of Your Bicycle
- 14. Object Oriented Programming • In OOP, problem is divided into number of entities called objects and then builds data and functions around these objects • It ties the data more closely to the functions that operate it and protects it from accidental modification from the outside functions • Data of an object can only be accessed by the functions associated with that object • Communication of the objects done through functions.
- 15. Classes • Classes are user-defined data types • Objects are variables of a class • Once a class has been defined, we can create any number of objects from the Class • A class thus can be said as a collection of similar objects of same type.
- 16. Example • Let us consider a software that involves renting cars. • We can have a class and objects as below
- 17. Example Let us consider a software that involves a zoo. What are some of the classes and objects to be created .
- 18. Answer
- 19. Core Concepts
- 20. Encapsulation • Encapsulation is the first pillar or principle of object-oriented programming • In simple words, “Encapsulation is a process of binding data members (variables, properties) and member functions(methods) into a single unit” • And a Class is the best example of encapsulation • Data Hiding from all external Classes
- 21. Encapsulation
- 22. Encapsulation in Real Life •Has prescription •Does not have direct contact to the medicines Patient •Has Access to the medicine •Returns the right medicine •Reduces risk of you getting wrong medicine Chemist •Can only be accessed by chemists •Several medicines available for different treatments Medicines
- 23. Encapsulation in OOP •Has no direct access to data in the medicine class External Classes •Controls access and manipulation of data in the medicine class •They are wrapped in the class Functions •Medicine Class •Contains both member functions and Variables •Determines how accessible the data is to outside world Medicines
- 24. Encapsulation in OOP So, Encapsulation means hiding the important features of a class which has no usefulness being exposed to outside of the class and exposing only the necessary things of the class.
- 25. Abstraction Abstraction is about describing something at a conceptual level while leaving out the details. example, we may talk about a vehicle without being explicit if it's a ship or a car.
- 26. Example of Abstraction When using the tv remote control, you do not bother about how pressing a key in the remote changes the channel on the TV. You Just know that pressing the “+” volume button will increase the volume.
- 27. Example of Abstraction • A class can be abstract as well meaning , it can provide you functions without their implementation • For example, if our class was a remote control , it will give us the method IncreaseVolume() without details of how It will be done . Such a method is called an abstract method
- 28. Example of Abstraction • You cannot instantiate this class Animal myObj = new Animal(); // Will generate an error • You can only Inherit this class
- 29. Inheritance • The mechanism of deriving a new class from an old class is called inheritance or derivation • The Old class is known as base class while new class is known as derived class or sub class • Inheritance is the most powerful feature of OOP. • Gives the sub class access to methods of based class
- 30. Example If a child is as Tall as his dad and Fair as his mom , we usually say the child has inherited these features from his father and mother.
- 31. Example using System; namespace MyApplication { class Vehicle // Base class { public string brand = "Ford"; // Vehicle field public void honk() // Vehicle method { Console.WriteLine("Tuut, tuut!"); } } } • The Base class here is Vehicle • It has Properties (Brand) and an implemented Method honk
- 32. Example using System; namespace MyApplication { class Car : Vehicle // Derived class { public string modelName = "Mustang"; // Car field } } • The Base class here is Vehicle • The Car class is inheriting the vehicle class and thus Will have access to the honk method in the Vehicle class. • Inheritance is shown by the “:” sign . Colon.
- 33. Example Code Snippet using System; namespace MyApplication { class Program { static void Main(string[] args) { // Create a myCar object Car myCar = new Car(); // Call the honk() method (From the Vehicle class) on the myCar object myCar.honk(); // Display the value of the brand field (from the Vehicle class) and the value of the modelName from the Car class Console.WriteLine(myCar.brand + " " + myCar.modelName); } } }
- 34. Inheritance • Through Effective use of inheritance , you can save a lot of time in your programming and reduces errors • This will also increase the quality of the work and productivity
- 35. Polymorphism • Polymorphism means "many forms", and it occurs when we have many classes that are related to each other by inheritance • Inheritance lets us inherit fields and methods from another class. Polymorphism uses those methods to perform different tasks. This allows us to perform a single action in different ways.
- 36. Example For example, think of a base class called Animal that has a method called animalSound(). Derived classes of Animals could be Pigs, Cats, Dogs, Birds - And they also have their own implementation of an animal sound (the pig oinks, and the cat meows, etc.):
- 37. Example class Animal // Base class (parent) { public void animalSound() { Console.WriteLine("The animal makes a sound"); } } class Pig : Animal // Derived class (child) { public void animalSound() { Console.WriteLine("The pig says: wee wee"); } }
- 38. Next Lecture Object Oriented Programming Implementation Building a Game with C# Unity 3D and C# • Encapsulation • Inheritance • Polymorphism • Abstraction Modelling our Game as OOP