Difference between revisions of "OOP Class5"

esse quam videri
Jump to: navigation, search
(→‎Operator Overloading)
 
(56 intermediate revisions by 3 users not shown)
Line 1: Line 1:
−
[[Category:OOP]]
+
[[Category:IAM Classes]]
−
==Properties Private instance data members - accessors==
 
−
Micorsoft has stared calling private varables with accessors Properties
 
−
 
 
−
Private class memebers the use get and set keyword to set and retrieve data. Get and set are known as accessor methods private members are helpfull when you want to also do other things when a data member is changed or change the rutern value under certian conditions. C# Programmer's Reference - Accessors http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfaccessorspg.asp. Lastly accessor also make read only and write only variables possible
 
−
 
 
−
<csharp>//private string color read/write
 
−
private string color;
 
−
 
 
−
public string Color
 
−
{
 
−
  get
 
−
  {
 
−
  return color;
 
−
  }
 
−
  set
 
−
  {
 
−
  color = value;
 
−
  }
 
−
}
 
−
 
 
−
//private string color read only
 
−
private string color;
 
−
 
 
−
public string Color
 
−
{
 
−
  get
 
−
  {
 
−
  return color;
 
−
  }
 
−
}</csharp>
 
−
 
 
−
 
 
 
==This keyword==
 
==This keyword==
  
 
The this keyword used within a class refers to the current instance of the class
 
The this keyword used within a class refers to the current instance of the class
  
−
<csharp>public Time( int CurrentYear, int CurrentDay)
+
<syntaxhighlight lang="csharp">public Time( int CurrentYear, int CurrentDay)
 
{
 
{
 
  this.Year = CurrentYear;
 
  this.Year = CurrentYear;
 
  this.Day = CurrentDay;
 
  this.Day = CurrentDay;
−
}</csharp>
+
}</syntaxhighlight>
  
−
Here's a class of dogs that return differnt color depending on whether on not they are clean. It uses private private instance data memebrs and the this keyword
 
  
−
<csharp>//Accessor for private color allow color to be set and return color or 'dirty' + color
 
−
    public string Color
 
−
    {
 
−
        get
 
−
        {
 
−
            //if current dog isClean the return dogs color
 
−
            if (this.isClean == true)
 
−
            {
 
−
                return color;
 
−
            }
 
−
            //else return 'dirty' and the dogs color
 
−
            else {
 
−
                return "dirty " + color;
 
−
            }
 
−
        }
 
−
        set
 
−
        {
 
−
          color = value;
 
−
        }
 
−
    }</csharp>
 
  
−
console /infod/jeff/classSource/class4/dogAccessor.cs - source
+
==What is UML==
−
web /infod/jeff/classSource/class4/dogAccessor.aspx - source
+
;UML : Unified Modeling Language.
 +
:"A modeling language is a language whose vocabulary and rules focus on the conceptual and physical representation of a system"
 +
The Unified Modeling Language User Guide, Booch Rumbaugh Jacobson
 +
ACM Press, Addison Wesley 1999 ISBN 0201571684
 +
[http://www.amazon.com/gp/product/0201571684/104-7742183-3467114?v=glance&n=283155 The Unified Modeling Language User Guide]
 +
==Simple Notation==
 +
Class notation in UML
  
−
Dog private members, Overloaded with method class definition
+
The name of the Class should go inside of a box
  
−
<csharp>//Dog private members, Overloaded  with method class definition
+
{| align="center" cellspacing="0" style="border:2px solid black;"
−
public class Dog
+
|Class Name
−
{
+
|}
−
private string name; // the dog's name
 
−
private int age; // the dog's age
 
−
private int weight; // the dog's weight
 
−
private string barkSound; // the sound of the dog's bark
 
−
private int barkCount; // how many times the dog has barked
 
−
 
−
public Dog()
 
−
{
 
−
barkSound = "Woof!!!";
 
−
}
 
−
public Dog(string newName)
 
−
{
 
−
name = newName;
 
−
barkSound = "Woof!!!";
 
−
}
 
−
public Dog(string newName, string newBarkSound )
 
−
{
 
−
name = newName;
 
−
barkSound = newBarkSound;
 
−
}
 
  
−
public string Name
 
−
{
 
−
get
 
−
{
 
−
return name;
 
−
}
 
−
set
 
−
{
 
−
name = value;
 
−
}
 
−
}
 
−
public int Age
 
−
{
 
−
get
 
−
{
 
−
return age;
 
−
}
 
−
set
 
−
{
 
−
age = value;
 
−
}
 
−
}
 
−
public int Weight
 
−
{
 
−
get
 
−
{
 
−
return weight;
 
−
}
 
−
set
 
−
{
 
−
weight = value;
 
−
}
 
−
}
 
−
public string BarkSound
 
−
{
 
−
get
 
−
{
 
−
return barkSound;
 
−
}
 
−
set
 
−
{
 
−
barkSound = value;
 
−
}
 
−
}
 
−
public int BarkCount //you can't set bark count
 
−
//it only increments from the Bark() method
 
−
{
 
−
get
 
−
{
 
−
return barkCount;
 
−
}
 
−
}
 
−
   
 
−
    public string About()
 
−
{
 
−
//return a string with some information about the dog
 
−
        string about = "";
 
−
//this refers to current object
 
−
about +=("\nThe dogs name is " + this.name + ".");
 
−
about +=("\nIt is " + this.age + " years old.");
 
−
about +=("\nIt weighs " + this.weight + " lb(s).");
 
−
about +=("\nIts bark sounds like '" + this.barkSound + "'");
 
−
about +=("\nIt has barked " + this.barkCount + " time(s)" );
 
−
        about += about.Replace("\n","
 
−
");
 
−
        return about;
 
−
}
 
  
−
public void Bark() {
+
Then Two lines are added. The first line separates Attributes. The second line separates Operations.
−
//make dog bark
+
Attributes are the equivalent of fields or properties in c# and Operations are the same as methods.
−
Console.WriteLine (this.Name + " says " + this.barkSound);
 
−
//add 1 to the number of times the dog has barked
 
−
this.barkCount++ ;
 
−
}
 
−
public void Eat() {
 
−
//put eat code here
 
−
}
 
−
}</csharp>
 
  
−
console
+
{|  align="center" border = 0
 +
|
  
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class4/dogOverloadMethodScoped.cs dogOverloadMethodScoped.cs]
+
{|  cellspacing="0" style="border:2px solid black;"
 +
|Class Name
 +
|-
 +
| style="border-Top:2px solid black;" |&nbsp;
 +
|-
 +
| style="border-Top:2px solid black;" |&nbsp;
 +
|}
  
 +
|
  
−
Real barking dogs...
+
{| align="center" cellspacing="0" Border = 0
 +
| <--'''Class Name'''
 +
|-
 +
|  <--'''Attributes'''
 +
|-
 +
| <--'''Opertaions'''
 +
|}
  
−
[http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class4/DogBark DogBark]
+
|}
  
−
an example of how you don't need to know how all of the classes work just how to use them
 
  
 +
A Rectagle Class might look like this
  
 +
{|  align="center" cellspacing="0" style="border:2px solid black;"
 +
|Rectangle
 +
|-
 +
| style="border-Top:2px solid black;" | height
 +
|-
 +
| width
 +
|-
 +
| style="border-Top:2px solid black;" | area()
 +
|-
 +
| add()
 +
|-
 +
| move()
 +
|-
 +
| copy()
 +
|-
 +
| isEmpty()
 +
|}
  
−
==In Class Project==
+
You can also specify Attribute types with a :
−
In class build traingle class.
 
−
Properties
 
  
−
* sideA
+
{|  align="center" cellspacing="0" style="border:2px solid black;"
−
* sideB
+
|Rectangle
−
* sideC
+
|-
 +
| style="border-Top:2px solid black;" | height : Float
 +
|-
 +
| width : Float
 +
|-
 +
| style="border-Top:2px solid black;" | area()
 +
|-
 +
| add()
 +
|-
 +
| move()
 +
|-
 +
| copy()
 +
|-
 +
| isEmpty()
 +
|}
  
−
Methods
+
Default vlaues are specified with =
  
−
* Area //A method that reurn the area of the triangle
+
{|  align="center" cellspacing="0" style="border:2px solid black;"
 +
|Rectangle
 +
|-
 +
| style="border-Top:2px solid black;" | height : Float = 6.0
 +
|-
 +
| width : Float = 4.0
 +
|-
 +
| style="border-Top:2px solid black;" | area()
 +
|-
 +
| add()
 +
|-
 +
| move()
 +
|-
 +
| copy()
 +
|-
 +
| isEmpty()
 +
|}
  
−
      use Heronian formula which is able to compute the area of a triange by knowing the length of the three sides.
 
−
      triangle area given a,b,c = sqrt(s(s-a)(s-b)(s-c)) when s = (a+b+c)/2 (Heron's formula)
 
  
−
<csharp>// Heronian formula
+
Operator return type are also specifed with a :. Opertor parameter signatures are specified by ( '''name''' : '''Type''' )
−
double s = (a + b + c) / 2.0;
 
−
double dArea = Math.Sqrt(s*(s-a)*(s-b)*(s-c));
 
−
</csharp>
 
  
−
Once you have built the triangle class build a class to test it.
+
{|  align="center" cellspacing="0" style="border:2px solid black;"
−
The test class should create a triangle with
+
|Rectangle
−
sideA= 3
+
|-
−
sideB= 4
+
| style="border-Top:2px solid black;" | height : Float = 6.0
−
sideC= 5
+
|-
 +
| width : Float = 4.0
 +
|-
 +
| style="border-Top:2px solid black;" | area() : Float
 +
|-
 +
| add()(r:Rectangle)
 +
|-
 +
| move()
 +
|-
 +
| copy() :Rectangle
 +
|-
 +
| isEmpty() : Boolean = true
 +
|}
  
−
and then display the area as text in the console.
+
==UML Resources==
 +
[http://www.gnome.org/projects/dia/ Dia A Drawing Program]
  
−
http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class4/tri_class.cs tri_class.cs]
+
[http://dia-installer.sourceforge.net/ Dia for windows]
  
−
=Class Relationship=
+
[http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class6/DiagramDog Dog Diagrams with Dia]
  
−
Look a classes from homework.
+
==access-modifiers==
 +
public +
 +
:most permissive access. No restrictions on access
 +
private -
 +
:least permissive access level. Only available to the class in which it was declared
  
−
Discuss TV and Radio class
+
Public Dog
 +
[[Image:DogSimpleUML.png]]
  
−
More objects
+
Dog with private age
 +
[[Image:DogsimpleAgePrivate.png]]
  
 +
==Dog Examples==
 +
Simple Dog Class from week 5 [http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class6/DiagramDog/DogSimple.cs DogSimple.cs - source]<br />
 +
[[Image:DogSimple.png]]
 +
<syntaxhighlight lang="csharp">using System;
  
−
 
+
//Dog simple class definition
−
==Shared Members - static members==
+
public class Dog
−
aka Shared Properties
 
−
 
 
−
Static - A type of member modifier that indicates that the member applies to the type rather than an instance of the type
 
−
 
 
−
<csharp>public class Dog
 
 
{
 
{
−
//some code
+
public string Name; // the dog's name
−
 
+
public int Age; // the dog's age
−
static private int dogCount; // total number of dogs
+
public int Weight; // the dog's weight
−
 
+
public string BarkSound; // the sound of the dog's bark
 +
 
public Dog()
 
public Dog()
 
{
 
{
−
barkSound = "Woof!!!";
+
BarkSound = "Woof!!!";
−
//Add a dog to the total dog count
 
−
dogCount++;
 
 
}
 
}
−
public Dog(string newName)
 
−
{
 
−
name = newName;
 
−
barkSound = "Woof!!!";
 
−
//Add a dog to the total dog count
 
−
dogCount++;
 
−
}</csharp>
 
  
−
Static dougCount Example <br />
+
public void Bark() {
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/dogStatic.cs dogStatic.cs] - source
+
//put bark code here
 +
}
 +
public void Eat() {
 +
//put eat code here
 +
}
 +
}</syntaxhighlight>
  
−
==Class Relationships==
 
−
Four Class Relation ships
 
  
−
* Association - 'Uses A'
+
Dog UML with Types
−
* Containment - 'Has A'
 
−
* Inheritance - 'Is A'
 
−
* Interfaces - implements or derives from We'll do this next week in [[OOP Class6]]
 
  
−
==Association - 'Uses A'==
+
Dog Class with Types from week 4 [http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class6/DiagramDog/DogWithTypes.cs DogWithTypes.cs - source]<br /><br />
−
 
+
[[Image:DogWithTypes.png]]
−
A dog uses a hydrant to relieve them self.
+
<syntaxhighlight lang="csharp">using System;
−
 
+
−
<csharp>//Dog simple class definition
+
//Dog simple class definition
 
public class Dog
 
public class Dog
 
{
 
{
−
    //some dog code...
+
public string Name; // the dog's name
 +
private int age; // the dog's age
 +
public int Weight; // the dog's weight
 +
public string BarkSound; // the sound of the dog's bark
 +
private int barkCount;    //The number of time the dog has barked
 +
public Dog()
 +
{
 +
BarkSound = "Woof!!!";
 +
}
 +
 +
public string Bark() {
 +
string strBark = this.BarkSound;
 +
        barkCount ++;
 +
        return strBark;
 +
}
 
      
 
      
−
    public void Relieve(Hydrant h)
+
public void Eat() {
−
    {
+
//put eat code here
−
    h.Clean = false;
+
}
−
    }
+
}</syntaxhighlight>
−
}  
+
 
 +
==Class Relationships==
 +
Four Class Relation ships
  
−
public class Hydrant
+
* Association - ''Uses A'' [[OOP Class6]]
−
{
+
* Containment - ''Has A'' [[OOP Class6]]
−
  public string Color; //the color of the hydrant
+
* Inheritance - ''Is A''
−
  public bool Clean;  //if the hydrant is clean or dirty
+
* Interfaces - '''implements or derives from''' We'll do this next week in [[OOP Class7]]
−
 
 
−
  public Hydrant()
 
−
  {
 
−
    Color = "red";
 
−
    Clean = true;
 
−
  }
 
−
 
 
−
  public override string ToString ()
 
−
  {
 
−
    if (this.Clean == true)
 
−
    {
 
−
    return ("The " + this.Color + " hydrant is clean.");
 
−
    }
 
−
    else
 
−
    {
 
−
    return ("The " + this.Color + " hydrant is not clean.");
 
−
    }
 
−
  }
 
−
}</csharp>
 
  
−
Dog Association example
+
==Inheritance - 'Is A'==
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/DogHydrant.cs DogHydrant.cs] - source
 
  
−
==Containment - 'Has A'==
+
[http://ia300033.us.archive.org/1/items/arsdigitac04n03/Lecture_03.html ArsDigita University Course 04: Object-oriented Program Design and Software Engineering - Lecture Notes 3]
−
A dog has an owner
 
  
 +
C# supports single class inheritance only. Therefore, you can specify only one base class to inherit from.
  
−
<csharp>Dog fido = new Dog("fido");
+
'''Sub''' class
−
fido.Owner = new Person("Sue");</csharp>
+
: a Sub class is a class that inherits properties and methods from another class. The class that sub class inherits from id the '''Super''' class
 +
'''Super''' class
 +
: a Super class that has other classes that inherit from it.
  
−
<csharp>//Dog simple class definition
+
[[Image:DogInheritance.png|frame|right|caption|The Mammal/Dog/Basengi inheritance relationship]]
−
public class Dog
 
−
{
 
−
    public string Name;        // the dog's name
 
−
    public string BarkSound;    // the sound of the dog's bark
 
−
    public Person Owner;    // the dogs owner
 
−
   
 
−
    public Dog(string dogName)
 
−
    {
 
−
        Name = dogName;
 
−
        BarkSound = "Woof!!!";
 
−
    }
 
  
−
    public string Bark() {
+
A '''Basenji''' is an African barkless dog.
−
        string s;
 
−
        s = this.Name + " says " + this.BarkSound;
 
−
        //Make sure the the dog has an owner
 
−
        if (!(this.Owner == null))
 
−
          s += "\n" + Owner.Name + " says be quiet.";
 
−
        return s;
 
−
    }
 
−
}   
 
  
−
public class Person
+
A '''Basenji''' ''is a'' '''Dog'''.
−
  {
 
−
    public string Name;      //the color of the hydrant
 
−
   
 
−
    public Person(string newName)
 
−
    {
 
−
      Name = newName;
 
−
    }
 
−
  }</csharp>
 
  
 +
A '''Dog''' ''is a'' '''Mammal'''.
  
−
Containment example<br>
+
In this case the '''Mammal''' class is the '''Super''' class to the '''Dog'''.
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/DogOwner.cs DogOwner.cs] -source
 
  
−
==Inheritance - 'Is A'==
+
The '''Basenji''' is the '''Sub''' class to the '''Dog''' class.
  
−
[http://ia300033.us.archive.org/1/items/arsdigitac04n03/Lecture_03.html ArsDigita University Course 04: Object-oriented Program Design and Software Engineering - Lecture Notes 3]
+
Here is how you would draw this with UML.
  
−
C# supports single class inheritance only. Therefore, you can specify only one base class to inherit from.
+
Lets start with the Dog/Basenji Relationship
  
−
A Basenji is an African barkless dog.
 
−
A Basenji is a dog.
 
 
syntax
 
syntax
  
−
<csharp>public class Basenji : Dog
+
<syntaxhighlight lang="csharp">public class Basenji : Dog
 
{
 
{
 
     //override constructor
 
     //override constructor
Line 385: Line 276:
 
         this.barkCount++ ;
 
         this.barkCount++ ;
 
     }
 
     }
−
}</csharp>
+
}</syntaxhighlight>
  
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/Basenji.cs Basenji.cs] -source
+
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/BasenjiInhertance.cs BasenjiInhertance.cs] -source
  
 
==Virtual Functions==
 
==Virtual Functions==
  
 
A class modifier that indicates that a method can be overridden by a derived class.
 
A class modifier that indicates that a method can be overridden by a derived class.
−
We will look at virtual function when we look at abstract classes
+
 
 +
By marking a function as '''virtual''' any class a class that sub classes the current class can '''override''' the function
  
 
==Abstract Classes==
 
==Abstract Classes==
 
  abstract - A class modifier that specifies that the class must be derived from to be instantiated.
 
  abstract - A class modifier that specifies that the class must be derived from to be instantiated.
  
−
<csharp>abstract public class Mammal
+
<syntaxhighlight lang="csharp">abstract public class Mammal
 
{
 
{
−
private string birth;
+
public string Birth;
−
private string skin;
+
public string Skin;
  
 
public Mammal()
 
public Mammal()
 
{
 
{
−
birth = " gives birth to live young.";
+
Birth = " gives birth to live young.";
−
skin = " has Hair.";
+
Skin = " has Hair.";
 
}
 
}
 +
}</syntaxhighlight>
  
−
public string Birth
+
Inheritance example /infod/jeff/classSource/class5/DogMammalInhertance.cs -source
−
{
+
 
−
get
+
===Polymorphic Types===
−
{
 
−
return birth;
 
−
}
 
−
}
 
−
public string Skin
 
−
{
 
−
get
 
−
{
 
−
return skin;
 
−
}
 
−
}
 
−
}</csharp>
 
  
−
Inheritance example /infod/jeff/classSource/class5/DogMammal.cs -source
+
;Polymorphism: poly means 'many' morph means 'form'. So a polymorphic type is many forms that have the same attributes and abilities
  
−
===Polymorphic Types===
 
 
[http://en.wikipedia.org/wiki/Polymorphism_%28computer_science%29 Polymorphism (computer science)]
 
[http://en.wikipedia.org/wiki/Polymorphism_%28computer_science%29 Polymorphism (computer science)]
−
Different types implementing the same functionality.<br>
+
 
 +
Different types implementing the same functionality.
 +
 
 
[http://www.webopedia.com/TERM/p/polymorphism.html  polymorphism webopedia]
 
[http://www.webopedia.com/TERM/p/polymorphism.html  polymorphism webopedia]
 +
 
The C# Station Tutorial - [http://www.csharp-station.com/Tutorials/Lesson09.aspx Lesson 9: Polymorphism]
 
The C# Station Tutorial - [http://www.csharp-station.com/Tutorials/Lesson09.aspx Lesson 9: Polymorphism]
  
−
<csharp>abstract public class Mammal
+
<syntaxhighlight lang="csharp">//Mammal class definition is it abstract
 +
abstract public class Mammal
 
{
 
{
−
private string name;
+
public string Name;
−
private string birth;
+
public string Brith;
−
private string skin;
+
public string Skin;
  
 
public Mammal()
 
public Mammal()
 
{
 
{
−
name = "none";
+
Name = "none";
−
birth = " gives birth to live young.";
+
Brith = " gives Brith to live young.";
−
skin = " has Hair.";
+
Skin = " has Hair.";
 
}
 
}
 +
 
 
 
public Mammal(string newName)
 
public Mammal(string newName)
 
{
 
{
−
name = newName;
+
Name = newName;
−
birth = " gives birth to live young.";
+
Brith = " gives Brith to live young.";
−
skin = " has Hair.";
+
Skin = " has Hair.";
 
}
 
}
  
−
public string Birth
 
−
{
 
−
get
 
−
{
 
−
return birth;
 
−
}
 
−
}
 
−
public string Skin
 
−
{
 
−
get
 
−
{
 
−
return skin;
 
−
}
 
−
}
 
−
public string Name
 
−
{
 
−
get
 
−
{
 
−
return name;
 
−
}
 
−
set
 
−
{
 
−
name = value;
 
−
}
 
−
}
 
 
public virtual void Bark()
 
public virtual void Bark()
 
{
 
{
 
Console.WriteLine("Some Mammals Bark.");
 
Console.WriteLine("Some Mammals Bark.");
 
}
 
}
 +
 
}
 
}
  
 +
//Dog simple class definition
 
public class Dog : Mammal
 
public class Dog : Mammal
 
{
 
{
Line 502: Line 364:
 
}
 
}
  
 +
//a basengi is a barkless dog
 
public class Basenji : Dog
 
public class Basenji : Dog
 
{
 
{
Line 515: Line 378:
 
Console.WriteLine("\nBasenjis dont bark.");
 
Console.WriteLine("\nBasenjis dont bark.");
 
}
 
}
−
    // some more code....
+
−
}</csharp>
+
// some more code....
 +
}
 +
 
 +
}</syntaxhighlight>
  
 
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/DogPoly.cs DogPoly.cs] -source
 
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/DogPoly.cs DogPoly.cs] -source
−
 
−
==Structs==
 
−
- remember these from week 2
 
−
 
−
Lightweight alternatives to classes. Structs do not support inheritance or destructors. Structs are value typed objects similar to ints bool etc... while classes are refence types. Structs are more memory efficient and and faster than classes.
 
−
Syntax
 
−
 
−
[ attributes] [access-modifiers] struct identifier
 
−
[:interface-list {struct members}
 
−
 
−
<csharp>struct Dog
 
−
{
 
−
public string name;
 
−
public string weight;
 
−
public int age;
 
−
}</csharp>
 
−
 
−
This is a pretty lightweight dog and is pretty useless as a dog (It's can't even bark what fun is that) so I won't make an example.
 
−
 
−
A good example of a stuct would be and something like a point. There may be many many points in a structure or graph and we would want the points
 
−
to be a lightweight as possible. Since the point object won't have an methods this is a good time to use a struct.
 
−
 
−
<csharp>struct Point
 
−
{
 
−
    public int x;
 
−
    public int y;
 
−
 
−
    public Point(int x, int y)
 
−
    {
 
−
        this.x = x;
 
−
        this.y = y;
 
−
    }
 
−
 
−
    public Point Add(Point pt)
 
−
    {
 
−
        Point newPt;
 
−
 
−
        newPt.x = x + pt.x;
 
−
        newPt.y = y + pt.y;
 
−
 
−
        return newPt;
 
−
    }
 
−
}</csharp>
 
−
 
−
==Operator Overloading==
 
−
 
−
<csharp>public static ClassType operator + ( object lhs, object rhs )
 
−
{
 
−
    ClassType c
 
−
    //code to implement class addition
 
−
    return c;
 
−
}</csharp>
 
−
 
−
Operator also refer to implicit and explicit conversions. Fractions make a good example for opertor overloading.
 
−
Fraction class
 
−
 
−
    * Create fractions from two numbers x/y or from whole numbers
 
−
    * Convert fractions to wholenumbers int
 
−
    * Convert fractions to float or double
 
−
    * OverRide ToString to decribe Fraction
 
−
 
−
 
−
Fraction Class Example of operator overloading.<br />
 
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/fractionConv.cs fractionConv.cs] - source<br />
 
−
Fraction class with implicit and explicit conversion<br />
 
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/fractionConv_NoTest.cs fractionConv_NoTest.cs] - source<br />
 
−
Fraction class with overridden operators<br />
 
−
[http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/fractionConvOver.cs fractionConvOver.cs] - source<br />
 
−
 
−
In class build a test application does thigs with frations.<br />
 
−
Using <br />
 
−
 
−
http://iam.colum.edu/oop/gbrowser.php?file=/classsource/class5/fractionConv_NoTest.cs fractionDone_NoTest.cs] create a test class that...
 
−
 
−
* Creates a fraction out of integers (ie cast int into fractions)
 
−
* Adds, subtracts, and reduces some fractions
 
−
* Creates floting point numbers out of fractions (is cast fraction into double)
 
−
* Checks the eqaulity of some fractions
 
  
 
==HomeWork==
 
==HomeWork==
Line 603: Line 391:
 
#Chapter 11 Inheritance and Polymorphism p 134-154
 
#Chapter 11 Inheritance and Polymorphism p 134-154
 
#Chpater 12 Operator Overloading p 155 - 172
 
#Chpater 12 Operator Overloading p 155 - 172
−
#chapter 13 Structs p 172 - 177 (relax its only 54 pages total)
 
  
 
'''DO'''
 
'''DO'''
 +
Create a super class and a sub class for your class.<br />
  
−
Extend the class that you worked on last week.<br />
+
http://iam.colum.edu/oop/classsource/class5/ConsoleApplicationInClass.zip
−
Demonstrate Inhertance 'Is A' with your class.<br />
 
−
*Make a class the subclasses  or superclasses your previous class.
 
−
 
 
−
Demonstrate
 
−
*Containment 'Has A'
 
−
**Make a class that contains or is contained by your old class
 
−
*Association - 'Uses A'
 
−
**Make a class that uses your original class
 
−
 
 
−
Thy to build a class that superclass you old tv and radio classes. Use inheritance to simplify your implementaion.
 
−
 
 
  
−
Quiz 2 next week
+
New One
 +
http://iam.colum.edu/oop/classsource/class5/ConsoleApplicationInClass5.zip
  
 
==Links==
 
==Links==

Latest revision as of 16:30, 10 June 2019

This keyword

The this keyword used within a class refers to the current instance of the class 

public Time( int CurrentYear, int CurrentDay)
{
 this.Year = CurrentYear;
 this.Day = CurrentDay;
}


What is UML

UML 
Unified Modeling Language.
"A modeling language is a language whose vocabulary and rules focus on the conceptual and physical representation of a system"

The Unified Modeling Language User Guide, Booch Rumbaugh Jacobson ACM Press, Addison Wesley 1999 ISBN 0201571684 The Unified Modeling Language User Guide

Simple Notation

Class notation in UML

The name of the Class should go inside of a box

Class Name


Then Two lines are added. The first line separates Attributes. The second line separates Operations. Attributes are the equivalent of fields or properties in c# and Operations are the same as methods.

Class Name
 
 
<--Class Name
<--Attributes
<--Opertaions


A Rectagle Class might look like this

Rectangle
height
width
area()
add()
move()
copy()
isEmpty()

You can also specify Attribute types with a :

Rectangle
height : Float
width : Float
area()
add()
move()
copy()
isEmpty()

Default vlaues are specified with =

Rectangle
height : Float = 6.0
width : Float = 4.0
area()
add()
move()
copy()
isEmpty()


Operator return type are also specifed with a :. Opertor parameter signatures are specified by ( name : Type )

Rectangle
height : Float = 6.0
width : Float = 4.0
area() : Float
add()(r:Rectangle)
move()
copy() :Rectangle
isEmpty() : Boolean = true

UML Resources

Dia A Drawing Program

Dia for windows

Dog Diagrams with Dia

access-modifiers

public +

most permissive access. No restrictions on access

private -

least permissive access level. Only available to the class in which it was declared

Public Dog DogSimpleUML.png

Dog with private age DogsimpleAgePrivate.png

Dog Examples

Simple Dog Class from week 5 DogSimple.cs - source
DogSimple.png 

using System;

//Dog simple class definition
public class Dog
{
 	public string Name;		// the dog's name
	public int Age;			// the dog's age
	public int Weight;			// the dog's weight
	public string BarkSound;	// the sound of the dog's bark
	
	public Dog()
	{
		BarkSound = "Woof!!!";
	}

	public void Bark() { 
		//put bark code here
	}
	public void Eat() {
		//put eat code here 
	}
}


Dog UML with Types

Dog Class with Types from week 4 DogWithTypes.cs - source

DogWithTypes.png 

using System;
 
//Dog simple class definition
public class Dog
{
 	public string Name;		// the dog's name
	private int age;			// the dog's age
	public int Weight;			// the dog's weight
	public string BarkSound;	// the sound of the dog's bark
	private int barkCount;    //The number of time the dog has barked
	public Dog()
	{
		BarkSound = "Woof!!!";
	}
 
	public string Bark() { 
		string strBark = this.BarkSound;
        barkCount ++;
        return strBark;
	}
    
	public void Eat() {
		//put eat code here 
	}
}

Class Relationships

Four Class Relation ships

  • Association - Uses A OOP Class6
  • Containment - Has A OOP Class6
  • Inheritance - Is A
  • Interfaces - implements or derives from We'll do this next week in OOP Class7

Inheritance - 'Is A'

ArsDigita University Course 04: Object-oriented Program Design and Software Engineering - Lecture Notes 3

C# supports single class inheritance only. Therefore, you can specify only one base class to inherit from.

Sub class

a Sub class is a class that inherits properties and methods from another class. The class that sub class inherits from id the Super class

Super class

a Super class that has other classes that inherit from it.
The Mammal/Dog/Basengi inheritance relationship

A Basenji is an African barkless dog.

A Basenji is a Dog.

A Dog is a Mammal.

In this case the Mammal class is the Super class to the Dog.

The Basenji is the Sub class to the Dog class.

Here is how you would draw this with UML.

Lets start with the Dog/Basenji Relationship

syntax 

public class Basenji : Dog
{
    //override constructor
    public Basenji() : base()
    {
        barkSound = "Basenjis don't bark, but they do howl and growl.";
        dogCount++;
    }
    public override void Bark()
    {
        Console.WriteLine("Basenjis dont bark.");
    }
		
		// some more code....
}

public class Dog
{		
	// some dog code...
	//methods need to be marked virtual or protected to be overridden
    public virtual void Bark() 
    { 
        //make dog bark
        Console.WriteLine (this.Name + " says " + this.barkSound);
        //add 1 to the number of times the dog has barked
        this.barkCount++ ;
    }
}

BasenjiInhertance.cs -source

Virtual Functions

A class modifier that indicates that a method can be overridden by a derived class.

By marking a function as virtual any class a class that sub classes the current class can override the function

Abstract Classes

abstract - A class modifier that specifies that the class must be derived from to be instantiated.

abstract public class Mammal
{
	public string Birth;
	public string Skin;

	public Mammal()
	{
		Birth = " gives birth to live young.";
		Skin = " has Hair.";
	}
}

Inheritance example /infod/jeff/classSource/class5/DogMammalInhertance.cs -source

Polymorphic Types

Polymorphism
poly means 'many' morph means 'form'. So a polymorphic type is many forms that have the same attributes and abilities

Polymorphism (computer science)

Different types implementing the same functionality.

polymorphism webopedia

The C# Station Tutorial - Lesson 9: Polymorphism 

//Mammal class definition is it abstract
abstract public class Mammal
{
	public string Name;
	public string Brith;
	public string Skin;

	public Mammal()
	{
		Name = "none";
		Brith = " gives Brith to live young.";
		Skin = " has Hair.";
	}
	
	
	public Mammal(string newName)
	{
		Name = newName;
		Brith = " gives Brith to live young.";
		Skin = " has Hair.";
	}

	public virtual void Bark()
	{
		Console.WriteLine("Some Mammals Bark.");
	}

}

//Dog simple class definition
public class Dog : Mammal
{
	public string BarkSound;	// the sound of the dog's bark
	
	public Dog(string newName)
	{
		Name = newName;
		BarkSound = "Woof!!!";
	}

	public override void Bark() { 
		base.Bark();
		Console.WriteLine(this.Name + " says " + this.BarkSound);
	}
	public void Eat() {
		//put eat code here 
	}
}

//a basengi is a barkless dog
public class Basenji : Dog
{
	//override constructor
	public Basenji(string newName) : base(newName)
	{
		BarkSound = "basenjis don't bark, but they do howl and growl.";
	}
	
	public override void Bark()
	{
		base.Bark();
		Console.WriteLine("\nBasenjis dont bark.");
	}
		
	// some more code....
}	

}

DogPoly.cs -source

HomeWork

READ

  1. Chapter 9 Inside Methods p 111-123
  2. Chapter 11 Inheritance and Polymorphism p 134-154
  3. Chpater 12 Operator Overloading p 155 - 172

DO Create a super class and a sub class for your class.

http://iam.colum.edu/oop/classsource/class5/ConsoleApplicationInClass.zip

New One http://iam.colum.edu/oop/classsource/class5/ConsoleApplicationInClass5.zip

Links

The C# Station Tutorial - Lesson 7: Introduction to Classes
The C# Station Tutorial - Lesson 8: Class Inheritance
The C# Station Tutorial - Lesson 9: Polymorphism
The C# Station Tutorial - Lesson 10: Properties
The C# Station Tutorial - Lesson 12: Structs
The C# Station Tutorial - Lesson 13: Interfaces
The C# Station Tutorial - Lesson 4: C# Fundamentals

Retrieved from "https://imamp.colum.edu/mediawiki/index.php?title=OOP_Class5&oldid=23755"