![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();
}
}
}](https://image.slidesharecdn.com/csharp101-introtoprogramming-160720173120/85/C-101-Intro-to-Programming-with-C-21-320.jpg)
![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();
}
}
}](https://image.slidesharecdn.com/csharp101-introtoprogramming-160720173120/85/C-101-Intro-to-Programming-with-C-35-320.jpg)
![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]);
}](https://image.slidesharecdn.com/csharp101-introtoprogramming-160720173120/85/C-101-Intro-to-Programming-with-C-68-320.jpg)
C# 101: Intro to Programming with 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
- 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
- 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
- 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