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BKIndex dotnet lecture01 session1 module1 2 3 4 5 operators constructs arrays

Chapter 1


Objectives
 Explain the need for C#
 Discuss flow control of a C# program
 Explain the fundamental data types in C#
 Discuss the concept of Boxing and UnBoxing
 Discuss Structures in C#
 Discuss Enumeration types
Programming in C# /
 Compile and run a C# program
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Microsoft .net

 Represents a new platform for developing
windows & web applications.
 Supports more than 20 languages.
 Revolutionizes facilities available for Windows

programming.
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Introduction to C#
 Takes full advantage of the .net Platform.
 The most efficient compiler in the .net family.
 A modern replacement for C++.
 Enhances developer productivity and increases
safety, by enforcing script type checking.
 Allows restricted use of native pointers.

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C# Program Flow
 A simple C# program:

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C# Constructs (1)
 Variables in C# are declared as follows:

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C# Constructs (2)
 If you want to use any keyword as the
variable name, you have to prefix the
variable name with @.

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Default Values (1)
 Variables in C# are automatically
assigned a
default value upon creation.

 Output:
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Default Values (2)
 The default values of the common data types:

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Input / Output In C# (1)
 Uses methods of the Console class in the
System namespace.
 The most widely used methods are:

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Input / Output In C# (2)

 The highlighted line acts as a placeholder where
Programming
in C#will
/ be
the value of the specified variable
(result)
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displayed.


Input / Output In C# (3)

 The program will accept a line from the user and
Programming in C# /
echo it back as output.
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The if construct
 Performs conditional branching.
 Syntax :

 The expression always requires to
Programming in C# /
evaluate to
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an expression of Boolean type.


Selection Statement

 The above piece of code will display an
error message:
Error CS0029 : Cannot implicitly convert type 'int' to 'bool'
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The switch Statement
(1)
 The switch statement can be used in place
of
multiple if statements
 Syntax:

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The switch Statement
(2)
 Example:

 It is mandatory to specify a break
statement
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for each and every case block.


Iteration
Constructs
 Performs
a certain set of instructions a
certain
number of times or while a specific
 condition
Types of iteration constructs:
is true.

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The while loop
 The while loop iterates through the
specified
statements
till the specified condition is
 Syntax
:
true.
 The break statement breaks out of the loop at
anytime.
 The continue statement skips
the current
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in C# /
iteration and begins with the
next
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iteration.


The do loop
 Syntax:

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The for loop
 Syntax :

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The foreach loop (1)
 The foreach loop is used to iterate through a
collection or an array.
 Syntax:

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The foreach loop (2)
 Example:

 Output:
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Constructors in C#
 A constructor in C# has the same
name as
the class.

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Destructors in C#
 A destructor in C# also has the same name
as the class preceded by a tilde (~).

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Fundamental Types Of C#
(1)
 C# divides data types into two fundamental
categories:

- int, char and structures

- classes, interfaces, arrays and strings
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