6 class and methods
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Class and Objects
Object-oriented programming
Programming languages designed based on data and ways to
manipulate data.
Procedural Languages (Pascal, C) focus on ways
Object-oriented Languages (C#, Java) focus on data
Features
Abstraction Encapsulation
Inheritance
Polymorphism
Focus only the required information from objects
Features
Abstraction
Encapsulation Inheritance
Polymorphism
Hide details of what a class contains
Features
Abstraction
Encapsulation
Inheritance Polymorphism
Create a new class based on the attributes and methods of an existing class
Features
Abstraction
Encapsulation
Inheritance
Polymorphism
Behave differently in different situations
Class
Class – should & cannot
Should be a noun
first letter capitalized
simple, descriptive, meaningful
Cannot
in mixed case
C# keyword
begin with a digit except @, _
Methods
Method – can & cannot
Can
begin with a letter, _ or @
Cannot C# keyword
contain space
begin with digit
Static methods
called without creating any objects of the class
refer only to static variables and other static methods of class.
https://gist.github.com/2349658
Static methods
Only one copy of static variable is shared by all the objects of the class.
Access Modifiers
Access Modifiers
Ref
causes arguments to be passed in a method by reference
https://gist.github.com/2344456
Out
similar to ref but no required the variables that are passed by
reference to be initialized https://gist.github.com/2344483
Method overloading
Method overloading
every method has a signature which comprises
the number of params
the data types of params
the order of params
Should and avoid
Methods to be overloaded should perform the same task
The signatures of the overloaded must be unique
Return type is not a part of the signature
The ref and out parameters can be included as a part of the signature
This keyword
refer to the current object of the class.
cannot use this keyword with static variables and method
https://gist.github.com/2344534
Constructors and Destructors
Constructors
initialization
no return type
possible to have overloaded constructors
https://gist.github.com/2344570
Default Constructors
C# creates a default constructors for a class if no constructor is
specified within the class. It automatically initializes all the numeric data type instance variables to zero.
If you define a constructor in the class, the default constructor is no longer used.
Static Constructors
initialize static variables of the class and to perform a particular
action only once.
is invoked before any static member of the class is accessed.
does not take any parameters and does not use any access modifiers because it is invoked directly by the CLR instead of the object.
Certainly, cannot access non-static data member. https://gist.github.com/2344643
Constructor Overloading
https://gist.github.com/2344673
Destructors
invoked automatically when the objects are not in use
only one destructor in a class
cannot be overloaded or inherited
cannot be explicitly invoked
cannot specify access modifiers and cannot take parameters
https://gist.github.com/2344708
Garbage Collector