An introduction to programming with Microsoft C#

1. C# 101: Intro to C# Programming

2. Introduction
• Your Name
• Your day job
• Your last holiday destination?

3. C# 101
• C# Fundamentals
– Setting up your development environment
– Language Overview
– How C# Works
– Writing your first program
– Built-in Data Types
– Conditionals and Loops

4. C# 102
• Object-oriented Programming
– Classes and Objects
– Polymorphism, Inheritance and Encapsulation
– Functions and Libraries

5. C# 103
• Data Structures
– Arrays
– Collections

6. C# 101: Introduction to C#
Setting up your Development
Environment

7. Installing Integrated Development Kit
• Download latest VS IDE from
https://www.visualstudio.com/en-
us/downloads/download-visual-studio-vs.aspx

8. What is an IDE?
• IDE = Integrated Development Environment
• Makes you more productive
• Includes text editor, compiler, debugger,
context- sensitive help, works with different
SDKs
• Visual Studio is the most widely used IDE

9. Installing Visual Studio
• Download and install the latest Visual Studio
for .Net framework(64 Bit version) from
https://www.microsoft.com/en-
gb/download/details.aspx?id=30653
• To start Visual Studio
– On PC, double-click on Visual Studio

10. Hands-on Exercise
Visual Studio Setup & Demo

11. C# 101: Introduction to C#
Language Overview

12. C# Language Overview
• Object-oriented
• Widely available
• Widely used

13. C# Versions
• Brief History…
- C#'s principal designer and lead architect at Microsoft is Anders Hejlsberg, was previously
involved with the design of Pascal, Delphi and Visual J++
• Major Version Releases
– C# 1.0 (2002)
– C# 2.0 ( 2005)
– C# 3.0 (2008)
– C# 4.0 (2010)
– C# 5.0 (2012)
– C# 6.0 (2015)

14. Visual Studio Editions
• Visual Studio Standard Edition
• Visual Studio Enterprise Edition
• Visual Studio Community Edition
• Visual Studio Express Edition

15. .NET Framework
A programming infrastructure created by Microsoft for building,
deploying, and running applications and services that use .NET
technologies, such as desktop applications and Web services.
The .NET Framework contains three major parts:
the Common Language Runtime.
the Framework Class Library.
ASP.NET.
.NET framework is required to develop and compile programs
Developers must have this installed

16. C# 101: Introduction to C#
How C# works

17. How C# Works

18. C# File Structure

19. C# 101: Introduction to C#
Writing Your First Program

20. Hello, World!

21. Writing Your First C# Program
• Create a new project in your IDE named Csharp101
• Create a HelloWorld class in the src folder inside the Csharp101 project as illustrated
below.
using System;
namespace HelloWorldApplication
{
class HelloWorld
{
static void Main(string[] args)
{ /* my first program in C# */
Console.WriteLine("Hello World");
Console.ReadKey();
}
}
}

22. Compiling Your First Java Program
• Save the HelloWorld class in the IDE
• This automatically compiles the HelloWorld.cs file into
into a HelloWorld.class file
• Go to the folder you created the csharp101 project on
your hard disk and open the src folder.
• What do you see?

23. Running Your First C# Program
• Build and Run your program in Visual Studio
by Ctrl+Shift+B / F5

25. Anatomy of a C# Application
Comments Class Name
Access
modifier
Function/static
method
Arguments

26. Language Features

27. Introduction to C#
Built-in Data Types

28. Built-in Data Types
• Data type are sets of values and operations
defined on those values.

29. Basic Definitions
• Variable - a name that refers to a value.
• Assignment statement - associates a value
with a variable.

30. String Data Type
Data Type Attributes
Values sequence of characters
Typical literals “Hello”, “1 “, “*”
Operation Concatenate
Operator +
• Useful for program input and output.

31. String Data Type

32. String Data Type
• Meaning of characters depends on context.

33. String Data Type
Expression Value
“Hi, “ + “Bob” “Hi, Bob”
“1” + “ 2 “ + “ 1” “ 1 2 1”
“1234” + “ + “ + “99” “1234 + 99”
“1234” + “99” “123499”

34. Hands-on Exercise
Command Line Arguments

35. Exercise: Command Line Arguments
• Create the C# program below that takes a name as command-line
argument and prints “Hi <name>, How are you?”
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string x;
System.Console.WriteLine("Enter your name");
x = Console.ReadLine();
System.Console.WriteLine("Hi {0} , How are you", x);
Console.ReadKey();
}
}
}

36. Integer Data Type
Data Type Attributes
Values Integers between -2E31 to +2E31-1
Typical literals 1234, -99 , 99, 0, 1000000
Operation Add subtract multiply divide remainder
Operator + - * / %
• Useful for expressing algorithms.

37. Integer Data Type
Expression Value Comment
5 + 3 8
5 – 3 2
5 * 3 15
5 / 3 1 no fractional
part
5 % 3 2 remainder
1 / 0 run-time error
3 * 5 - 2 13 * has
precedence
3 + 5 / 2 5 / has
precedence
3 – 5 - 2 -4 left associative
(3-5) - 2 -4 better style
3 – (5-2) 0 unambiguous

38. Double Data Type
• Useful in scientific applications and floating-
point arithmetic
Data Type Attributes
Values Real numbers specified by the IEEE 754 standard
Typical literals 3.14159 6.022e23 -3.0 2.0 1.41421356237209
Operation Add subtract multiply divide
Operator + - * /

39. Double Data Type
Expression Value
3.141 + 0.03 3.171
3.141 – 0.03 3.111
6.02e23 / 2 3.01e23
5.0 / 2.0 1.6666666666667
10.0 % 3.141 0.577
1.0 / 0.0 Infinity
Math.sqrt(2.0) 1.4142135623730951

40. C# Math Library
Methods
Math.sin() Math.cos()
Math.log() Math.exp()
Math.sqrt() Math.pow()
Math.min() Math.max()
Math.abs() Math.PI
http://java.sun.com/javase/6/docs/api/java/lang/Math.html

41. Hands-on Exercise
Integer Operations

42. Exercise: Integer Operations
• Create a C# class named IntOps in the C101 project that performs integer
operations on a pair of integers from the command line and prints the results.

43. Solution: Integer Operations
int num1, num2, sum, prod, quot, rem;
num1 = int.Parse(Console.ReadLine());
num2 = int.Parse(Console.ReadLine());
sum = num1 + num2;
prod = num1 * num2;
quot = num1 / num2;
rem = num1 % num2;
System.Console.WriteLine(" {0} : {1} = {2}", num1, num2,
sum.ToString());
System.Console.WriteLine(" {0} : {1} = {2}", num1, num2,
prod.ToString());
System.Console.WriteLine(" {0} : {1} = {2}", num1, num2,
quot.ToString());
System.Console.WriteLine(" {0} : {1} = {2}", num1, num2,
rem.ToString());
Console.ReadLine();

44. Boolean Data Type
• Useful to control logic and flow of a program.
Data Type Attributes
Values true or false
Typical literals true false
Operation and or not
Operator && || !

45. Truth-table of Boolean Operations
a !a a b a && b a || b
true false false false false false
false true false true false true
true false false true
true true true true

46. Boolean Comparisons
• Take operands of one type and produce an
operand of type boolean.
operation meaning true false
== equals 2 == 2 2 == 3
!= Not equals 3 != 2 2 != 2
< Less than 2 < 13 2 < 2
<= Less than or
equal
2 <= 2 3 <= 2
> Greater than 13 > 2 2 > 13
>= Greater than
or equal
3 >= 2 2 >= 3

47. Type Conversion
• Convert from one type of data to another.
• Implicit
– no loss of precision
– with strings
• Explicit:
– cast
– method.

48. Type Conversion Examples
expression Expression type Expression value
“1234” + 99 String “123499”
Int.Parse(“123”) int 123
(int) 2.71828 int 2
Math.round(2.71828) long 3
(int) Math.round(2.71828) int 3
(int) Math.round(3.14159) int 3
11 * 0.3 double 3.3
(int) 11 * 0.3 double 3.3
11 * (int) 0.3 int 0
(int) (11 * 0.3) int 3

49. Hands-on Exercise
Leap Year Finder

50. Exercise: Leap Year Finder
• A year is a leap year if it is either divisible by 400
or divisible by 4 but not 100.
• Write a java class named LeapYear in the Java101
project that takes a numeric year as command
line argument and prints true if it’s a leap year
and false if not

51. Solution: Leap Year Finder
int year = int.Parse(Console.ReadLine());
Boolean isLeapYear;
isLeapYear = (year % 4 == 0) && (year % 100 != 0);
isLeapYear = isLeapYear || (year % 400 == 0);
System.Console.WriteLine("the Year {0} is {1} ",
year.ToString(), isLeapYear.ToString());
Console.ReadLine();

52. Data Types Summary
• A data type is a set of values and operations on
those values.
– String for text processing
– double, int for mathematical calculation
– boolean for decision making
• Why do we need types?
– Type conversion must be done at some level.
– Compiler can help do it correctly.
– Example: in 1996, Ariane 5 rocket exploded after
takeoff because of bad type conversion.

53. Introduction to C#
Conditionals and Loops

54. Conditionals and Loops
• Sequence of statements that are actually
executed in a program.
• Enable us to choreograph control flow.

55. Conditionals
• The if statement is a common branching structure.
– Evaluate a boolean expression.
• If true, execute some statements.
• If false, execute other statements.

56. If Statement Example
if (Math.Sqrt(16) < 3)
System.Console.WriteLine("the number is less than 3");
Else
System.Console.WriteLine("the number is greater than 3");
Console.ReadLine();

57. More If Statement Examples

58. While Loop
• A common repetition structure.
– Evaluate a boolean expression.
– If true, execute some statements.
– Repeat.

59. For Loop
• Another common repetition structure.
– Execute initialization statement.
– Evaluate a boolean expression.
• If true, execute some statements.
– And then the increment statement.
– Repeat.

60. Anatomy of a For Loop
for (int i = 0; i < 5; i++)
{
System.Console.WriteLine("{0}", i);
}
Console.ReadLine();

61. Hands-on Exercise
Powers of Two

62. Exercise: Powers of Two
• Create a new C# project in Visual Studio named Pow2
• Write a C# class named PowerOfTwo to print powers of 2 that are
<= 2N where N is a number passed as an argument to the program.
– Increment i from 0 to N.
– Double v each time

63. Solution: Power of 2

64. Control Flow Summary
• Sequence of statements that are actually
executed in a program.
• Conditionals and loops enable us to choreograph
the control flow.
Control flow Description Example
Straight line
programs
all statements are executed in the
order given
Conditionals certain statements are executed
depending on the values of certain
variables
If
If-else
Loops certain statements are executed
repeatedly until certain conditions
are met
while
for
do-while

65. Homework Exercises
Java 101: Introduction to C#

66. Hands-on Exercise
Array of Days

67. Exercise: Array of Days
• Create a C# class named DayPrinter that prints
out names of the days in a week from an array
using a for-loop.

68. Solution: Arrays of Days
string[] daysOfTheWeek = { "Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday", "Friday", "Saturday" };
for(int i= 0;i < daysOfTheWeek.Length ;i++)
{
System.Console.WriteLine("{0}", daysOfTheWeek[i]);
}

69. Hands-on Exercise
Print Personal Details

70. Exercise: Print Personal Details
• Write a program that will print your name and
address to the console, for example:
Alex Johnson
23 Main Street
New York, NY 10001 USA

71. Further Reading