week 1
======
Unified (Universal) Modeling Language (UML)
- minus sign means private
+ plus sign means public

======================================
= 		Student 	     =
======================================
= - StudentID; string		     =	Private
= - name; string		     =
= - major; string		     =
= - gpa; double			     =
======================================
= + ApplyForAdmission(); bool	     =	Methods
= + EnrollAsStudent(); bool	     =
= + ChangeName();		     =
======================================

Information hiding: is an important component of OOP

Object is an instance of a class

Inheritance: it is defining a subclass of data objects that share some or all of the parent class characteristics.

Everything in C# is a class, even primitive variable types (int, float, doble, etc).  
All program statements in C# language are placed in a class.
Every C# program uses at last one class.

More OO than Java. C# is 100% OO.

C# is used to develop:
- mobile application
- dynamic web pages
- database access components
- windows desktop applications
- console based applications

.Net framework: is a layer between the OS and the application
*All code from each language (C#, C++, VB, J#) compiles to common Microsoft intermediate language (IL).

ADO.Net
Relational Databases

Why C#?:
- Most of the .Net class libraries are written in C#.
- These classes or templates were designed for reuse by any .Net supported languages

Through using the visual studio .Net IDE (Integrated Development Environment)  and .Net framework, C# provides an easy way to create graphical
user interface similar to VB.

C# also provides the pure data crunching horsepower to which C and C++ programmers are accustomed.

comments: /* */
	  //


using System 
^
(directive)

namespace program 
	   ^ (identifier)

When a console application is created visual studio .Net automatically references and imports the system namespace.
static 		void 		Main()
^ modifier	 ^return type	^ method

*static: implies that a single copy of the method is created and that we can access this method without having an object of the class

COnsole.WriteLine("Hello")
^class   ^method   ^param

cout		cin
Write()		Read()
WriteLine()	ReadLine() - enter multiple characters

Relationship between C# elements:
class library
namespace
classes
methods
statements

week 2
======
Identifiers -> 	predefined (system, main, console, wrtieline)
		userdefined (class)

C# is case sensitive.

Convention for capitalizaing indentifiers
- pascal case - first letter int the indentifier and the first letter of each subsequent concatenated word  are captelized (MyNameIs, AverageSalary)
- camel case - Hungarian Notation - first letter of an identifier is lowercase and the first letter of each subsequent concatentated word is capitalized (myNameIs, averageSalary)
- upper case - constant variables only - int INCHES_PER_FOOT = 12; (constant)

variables
---------
represents an area in the computer memory

Ex.
int homeWorkScore = 100;

Everytime we declare a variable int the C# language we are actually instantiating a class (creating an object)

Ex.
int homeWorkScore1;		--
int examNumber1;		 - created 3 objects
int numberOfPointsScored;	--

We are instantiating the int class when these objects are created

*In C# every program must include a class.
In C# a simple data type such as a whole number (int) is implemented as a class.

The primitive types (int, float) are classes in C#

object -> instance or occurnace of classes.
class -> an encapsulation of data and behaviors into a single package or unit

*CTS -> Common Type System (job interview question - what is advantage of using .net framework?)
- this enables cross language integration of code
- a single project or application can be written using multiple languages such as C#, J#, VB .Net

decimal - it is a new type not found in C++ or Java

double extraPerson = 3.50; - note nothing
float totalAmount = 23.57f; - note the "f"
decimal number = 0.07m; - not the "m"

boolean variable
----------------
bool moreDate = true;

- the bool type will not accept values such as 0, 1, or -1
- you can only use true or false

making data constant
--------------------
const - forces the functionality of not allowing the value to be changed

Ex.
const int SPEED = 70;

string
------
string fileLocation = "path";

+ (concatenation)

casts (type conversion)
-----------------------
c# provides an explicit type conversion trhrough type casting
(type) expression

Ex.
int value1 = 0, anotherNumber = 0;
double value2 = 100, anotherDouble = 100;
value1 = (int) value2;
value2 = (double) anotherNumber (not necessary, it will do this automatically)


Week 3
======
formatting output
-----------------
Console.out.writeline("The cost " + BEST_CARPET + "is {0:C}", totalCost);
							 ^ currency
We can format the results through the Console.out.write() method which calls the string format method automatically.

Character    Description
---------    -----------
C or c	     currancy ($)
F or f	     fixed point (automatically rounds)
N or n       number

Console.out.write("{0:C}", 28.76); => $28.76
Console.out.write("{0:F4}", 50); => $50.0000
Console.out.write("{0:N}", 700976); => 700,976
Console.out.write("Carpet {0:F} is {1:C}.", 9, 14); => Carpet 9 is $14.

Methods
-------
- operations or behavior for the data member of a class
- similar to functions, procedures
- it is a group of statements placed together under a single name
*- unlike some languages such as C and C++ that allows methods to be defined globally outside the class, we can't do this in C#.
- methods have to be included in a class

Modifiers
---------
- how to access data and members

const  (to indicate that the value is constant and can not be changed)
static (class.method - no object required to access members data, all main() method headings must include the static modifier)
public
private

write(), writeline() and readline() are all static methods of Console class.
Console.read()
^class   ^method

Methods defined as part of our user defined class, in which objects are instantiated, do not use static.
Methods that use static modifier are called class methods.

access modifiers in C#
----------------------
public - no restrictions on accessing public members of a class, other classes can reuse your class in different applications
protected - limited to the containing class or classes derived from the containing class
private - members are accessable only within the body of the class in which they are declared.
internal - limited to the current project
protected internal - limited to current project and classes derived from class

Method Names
------------
CalculateSalesTax() -> pascal format
*some languages place the void keyword inside the paranthesis in place of the parameter list to include that no parameters are needed.
*C# does not allow this and generates a syntax error.
 
Console.writeline("value1 {0} + value2 {1} " + " = value3 ({2})", 25, 75, (25+75)); => value1 25 + value2 75 = value3 (100)


week 4
======
Console.Read()     - input a character from keyboard
Console.ReadLine() - input string input from keyboard

week 5
======
Console.Read()

In unicode decimal representation for a -> 97 (ascii)

int aNumber;
aNumber.Console.Read();
Console.WriteLine("character: ", aNumber);
------
output
------
character: 97 (gives ascii code)


Console.WriteLine("character: ", (char) aNumber);
------				 ^^^^^^ casting
output
------
character: a (gives character)

another option
--------------
Console.WriteLine("The value: " + (char) Console.Read());
------				  ^^^^^^ casting
output
------
character: a (gives character)

- This single line is possible because the Console.Read() method allows the user to enter one character to read() method returns an int.  The
  int value is cast to a character for display purposes and the value is then concatenated to the end of the string with '+' operator.

Convert.ToDouble();
Convert.ToDecimal();
Convert.ToInt32();

Writing our own class methods
-----------------------------
modifier returntype methodname (parameters) - general form
{
}

returntype - specifies what kind of information is returned when the body of the method is finished executing.

user defined method - methods that do not return a value, called void method
		      methods that return a value, called return methods

***methods declared as "static" do not need an object to call (called class method), otherwise an object must be used.
			DisplayInstructions();
		static void DisplayInstructions() {}

The object concept
------------------
- By abstracting out the attributes (data) and behavior (method) we can create a class to serve a template from which many objects of that type can
  be instantiated

private member data
-------------------
The variables declared in the main method or other methods (our own) were only visible inside the body of the method in which they were declared.
If we declare field(variable) inside the class but not inside any specific method they become visible to all members of the class, including all of the method
members.

Usually private is for the data
usually public is for methods (functions)

When we write an instance method we do not use static keyword in the heading.  TO call an instance method, however, an object must be instantiated
and associated with a method.

Constructor
-----------
When we instantiate a class(object), we actually create an instance of the class, an object that takes up space and exists.

It is through a special method called constructors that we use to create instances of a class.
Constructors differ from other methods in 2 ways
------------------------------------------------
1) constructors do not return a value, but the keyword void is not included
2) constructors use the same identifier as the class name.
- always use the 'public' access modifier for constructors so that other classes can instantiate objects of their type.

week 6
======
When we instantiate a class (object), we actually create an instance of the class, an object that takes up memory space.
It is through a special method, called constructor that we use to create instances of class 
** Constructors differ with other methods
- have same name with a class
- it does not return value

A public access modifier is always associated with constructors so that other classes can instantiate objects of their type.

As with overloaded methods, signatures must differ for constructors.
You could not have one constructor that has the two string parameters or variables of firstName and lastName and then define another constructor that 
took string parameters of lastName & firstName.

accesser (getters)
------------------
public double GetNoOfQuareYards()
{
return noOfSquareYards
}
- data members usually declared as private

objects that instantiate one class may need to access members in another class by calling methods because methods are usually defined as public.

* A Standard Naming convention is to add "Get" on the front of accessor

mutator (setters)
-----------------
public void SetNoOfSquareYards()
{
}


* A Standard Naming convention is to add "Set" on the front of accessor

Property (new feature in C#)
----------------------------
public double Price()
{
	get
	{
	return PricePerYard;
	}

	set
	{
	PricePerSqYard = value;
	}
}

- provides a way to set/get private member data
** - get, set & value are not keywords

Objects
-------
classname objectname = new classname (arguements) - general form for declaring object & instantiating constructor
			^ keyword to call constructor*****

carpetCalculator pile = new carpetCalculator(37.90, 17.95);

call by reference - use ref instead of & in C++

Boolean - true / false

== equal to
!= not equal to

1 == 2 is false

Relational Operators
--------------------
greater than	 		8 > 5		true
less than			1 < 2		true
greater than or equal to 	100 >= 100	true
less than or equal to		100 <= 100	true

================================================================================================================
int aValue = 100;
int bValue = 1000;

char cValue = 'A';
string sValue = "cs958";
decimal money = 50.22m;
double dValue = 50.22;
================================================================================================================
expression				result				explanation
==========				======				===========
if (money == 1000.00)			syntax error			Type mismatch - money is decimal & 1000.00 is double
     ^decimal   ^ double

if (money == 50.22m)			true					
		^decimal

if (money != dValue)			syntax error			Type mismatch

if (aValue > bValue)			false				100 is not greater than 1000

if (sValue < "cs")			syntax error			Can not be used with string.   Could have used == or != though.

if (aValue > dValue)			true				Integer aValue is converted to double & compared

if (cValue = 'F')			syntax error			it is an assignment statement

if (cValue < 'f')			true				unicode A has a value of 65 and unicode A has a value of 102.

In C#, the == and != are defined to work with strings to compare the characters.

Logical Operators
=================
exp1		exp2		exp1 && exp2		exp1 || exp2		
T		T		T			T
T		F		F			T
F		T		F			T
F		F		F			F

if (aValue > bValue) & (count++ < 100)
- does counter to the right even if condition to the left is false

week 7
======
$ or | - useful for the situation that involves compound or complex expression in which you want the entire expression to be performed
	 whether the result of the conditional expression returns true

example:

value = 3;
value2 = 100;
(value > value2) & (count++ < 100) 

- In this case (False) but still the increment continues by replacing the $$ with $ but produces the same false result.
  However, the side effect of incrementing "count" will continue.

- one way statement 
    if (expression) 
	statement

- two way statement
	if (expression) 
		statement 
	else 
		statement

- nest if ... else statement - when we place an if within an if, we create a nested if .. else statement, also referred to as a nested if statement.
Long Way
--------
if (hourlyEmployee && hours > 40)
	bonus = 500;
if (hourlyEmployee && hours <= 40)
	bonus = 100;
if (! hourlyEmployee && yearsEmployed > 10)
	bonus = 300;
if (! hourslyEmployee && yearsEmployed <= 10)
	bonus = 200;
 
Nested Way
----------
bool hourlyEmployee;
double hours, bonus;
int yearsEmployed

if (hourlyEmployee)
	if (hours > 50)
		bonus = 500;
	else
		bonus = 100;
else
	if (yearsEmployed > 10)
		bonus = 300;
	else
		bonus = 200;

if (average > 89)
	grade = 'A';
elseif (average > 79)
	grade = 'B';
elseif (average > 69)
	grade = 'C'
elseif (average > 59)
	grade = 'D'
else
	grade = 'F'

Switch Selection Statement
--------------------------
The switch statement allows to perform a large number of alternatives based on a single variable
- can only test on an integral (int, short, long), character or string
***It can not be used with a double, decimal or float

Conditional Operator
--------------------
grade = examScore > 89 ? 'A' : 'C'
OR
if (examScore > 89)
	grade = 'A';
else
	grade = 'C';

general format: expression1 ? expression2 : expression3;

week 8
======
*** readline() - use if inputting more than one character

while loop - statement is a pretest loop

while (condition statement) {
   statements;
}

The conditional expression is tested before any of the statement in the body of the loop are performed.

Counter-controlled loop
-----------------------
When we know the number of times the statement must be executed

Sentinal-controlled loop
------------------------
Used for inputting data when we do not know the exact number of values to be entered.
Sentinal value - extreme or dummy value

Windows Applications using loops
--------------------------------
An event_driven model manages the interaction between the user and the GUI by handling the repetition for us.

C# has a predefined class called "MessageBox" that can be used for displaying information to users through it's show() method.

MessageBoxButtons.OK
MessageBoxButtons.OKCancel
MessageBoxIcon.Exclamation

State Controlled Loop
---------------------
Similar to sentinal-controlled loop, state-controlled loops stop when a certain state is reached.  Instead of requiring that the dummy
value be entered after all values are processed, a special variable is used with a state-controlled loop.

int[] number = {2, 4, 6, 8, 10}

foreach (int val in number) {
   Console.WriteLine(val);
}

output
======
2
4
6
8
10

Using the foreach statement -> available in C# only
---------------------------
The foreach statement is new to the C#.
It is used to move through a collection, such as an array.  Values are usually accessed in the array using the identifier and an
index representing the location of the element relative to the beginning of the first element.

Review
------
namespace
ASP.net - web applications
compiler
C# 100% Object Oriented
const - constant, does not change
static
IDE
scope of variables
parameters - out / ref / params (Which of the following is not a parameter type?)
switch, if/else statements
do/while - executes at least once
++p, p++