Introduction to C# Programming

1. Introduction to C# Programming ณภัทร สักทอง 1204452 Application Program Development

2. Outline 2 • Programming Languages • C# Language Overview

3. Programming Languages Programming Languages 3 • Program • A set of instructions for a computer to follow, written in specific programming language • Types of programming language • High-Level Language • Assembly Language • Machine Language

4. Programming Languages High-level VS Assembly VS Machine Language 4 • High-level Language • Nearly like human word • SUM := A * 2 + ALPHA/3; • Assembly Language • Some key words are understandable • MULL3A, #2, R • ADDL3R6, R7, SUM • Machine Language • Only “0” and “1” • 00011000011 • 00011001111 • 10011000111 Computer itself understands only Machine language

5. High-level language • static void Main( ){ Console.WriteLine("Hello World!");} • Assembly language • pushl %ebpmovl %esp, %ebpsubl $8, %espandl $-16, %esp Programming Languages • Machine language • 000110001100011100011000111010111100011000110001110 Language translator 5 Interpreter / Compiler Assembler Machine Hello World! _

6. Programming Languages High-Level Languages 6 • Functional Language • Lisp • Logic Language • Prolog • Procedural Language • Fortran • Cobol • Basic • C • Pascal • Object-Oriented Language • C++ • Java • C#

7. Outline 7 • Programming Languages • C# Language Overview

8. C# Language Overview A simple C# Program 8 Grouping using { }

9. C# Language Overview A simple C# Program 9 Statement ending with semicolon “;”

10. C# Language Overview A simple C# Program 10 C# syntax is case-sensitive namespace NAMEspace Main() main()

11. C# Language Overview A simple C# Program 11 White space means nothing static void Main(string[] args) { Console.WriteLine("Hello World!"); } static void Main(string[] args){ Console.WriteLine("Hello World!");}

12. C# Language Overview A simple C# Program 12 Anything between /* */ or after // is considered a comment Comments will not be translated static void Main(string[] args) //comment here { /* This is comment too. */ Console.WriteLine("Hello World!"); }

13. C# Language Overview Program Structure 13 • The starting point of the program is: • This is known as the method Main • A method is put inside a class • A class may be put inside a namespace static void Main () { ... starting point ... }

14. C# Language Overview Class Class namespace Program Structure 14 • In C# • A program can contain several namespaces • A namespace can contain several classes • A class can contain several methods • In other words • Think of a namespace as a container of classes • Think of a class as a container of methods method1 method2

15. C# Language Overview Program Structure 15 • For this 1204452 course • Program with only one class and at most one namespace • For now until sometime before midterm • Program with one method (i.e., Main) namespace HelloW { class HelloWClass { static void Main () { System.Console.WriteLine("Hello World!"); System.Console.ReadLine(); } } }

16. C# Language Overview Naming Rules 16 • Letters, digits and underscores(_) • First character letter or _ • Up to 63 characters long • Must not be a reserved word * Case Sensitive Example MSU53 ≠ msU53 ≠msu53

17. C# Language Overview Naming Rules 17 • Letters, digits and underscores(_) • First character letter or _ • Up to 63 characters long • Must not be a reserved word Example     name Name point9 9point     _data class class_A class_”A”

18. C# Language Overview C# Reserved Words 18

19. Any question?

20. C# Basic Concept

21. Outline 22 • C# Beginning • Variable and Constant • Expression • Statement • Modify-And-Assign • Math Class

22. C# Beginning C# Beginning 23 • The starting point of the program is: • This is known as the method Main • A method is put inside a class • A class may be put inside a namespace static void Main () { ... starting point ... }

23. C# Beginning Inside method Main 24 • Variable declarations • Statements static void Main(string[] args) { const double pi = 3.1416; int radius; double area; radius = int.Parse(Console.ReadLine()); area = pi*radius*radius; Console.WriteLine(area); }

24. Outline 25 • C# Beginning • Variable and Constant • Expression • Statement • Modify-And-Assign • Math Class

25. Variable & Constant What is Variable? 26 • A variable is used to store “data.” “It must be declared before used”

26. Variable & Constant Data Types 27

27. Variable & Constant C# Variable Declaration 28 • Syntax: • <datatype> <name>; • Example: • We can also assign its initial value. Example: int radius; double area; bool isokay; int k = 200; bool done = false;

28. C# Variable Declaration 29 • Syntax: • <datatype> <name_1>, <name_2>,..., <name_n>; • Example: • We can also assign its initial value. Example: int width, length, height; double mean, sd, max, min; bool isokay, isright, check; int width=5, length, height=4;

29. Test I - Variable Declaration 30 • Declare variable3,4,5 • Name3 : u • Name4 : tName5 : a • Type : double • Initial value3 : 5.0 • Initial value4 : nothing • Initial value5 : 9.8 • Declare variable1 • Name : num_Student • Type : interger • Initial value : nothing • Declare variable2 • Name : gender • Type : character • Initial value : m

30. Variable & Constant C# Constant Declaration 31 • Syntax: • const <datatype> <name> = <value>; • Example: const int radius = 15; const double area=1.5; const bool isokay=true; const string movie=”StarWarIII”; const char mckazine=‘m’;

31. Variable & Constant C# Constant Declaration 32 • Syntax: • const <datatype> <name_1> = <value_1>, <name_2> = <value_2>, ... , <name_n> = <value_n>; • Example: const int radius = 15, height = 5; const double area=1.5, wide=3.2, lenght = 4.1;

32. Test II - Constant Declaration 33 • Declare Constant • Name : e • Type : double • Initial value : 2.71828

33. Outline 34 • C# Beginning • Variable and Constant • Expression • Statement • Modify-And-Assign • Math Class

34. Expression Expression Arithmetic Expression Boolean Expression C# Expression 35

35. Expression Arithmetic Expression 36 • Operators • + - * / • % (remainder after division) • Example • 11 + 5  • 39 / 5  • 39.0/5  • 39 % 5  • 5.0 % 2.2  16 7 7.8 4 0.6

36. Expression Piority of Arithmetic Operators 37 Answer int a, b; a = 2-10*3/5+(6%4); b = 5*(15%4+(2-3))/9; a = -2 b = 1

37. Expression Calculation Priority 38 static void Main(){ int a,b,c,d; double e,f,g; a=2; b=7; c=5; d=c/a; e=5/b; f=5.0/2; g=5/2.0; } Answer d = 2 e = 0 f = 2.5 g = 2.5

38. Expression Boolean Expression 39 • Operators • Comparison • Equal == • Not equal != • Less < • Greater > • Less than or equal to <= • Greater than or equal to >= • Boolean • And && • Or || • Not! 0 and 0 = 0 0 and 1 = 0 1 and 0 = 0 1 and 1 = 1 0 or 0 = 0 0 or 1 = 1 1 or 0 = 1 1 or 1 = 1 not 0 = 1 not 1 = 0

39. Expression Example: Boolean Expression 40 • 10 > 50  • ’A’ < ’B’  • (3<2) || (2+5 > 6)  • (’a’ != ’z’) && !(9==0)  false true true true

40. Outline 41 • C# Beginning • Variable and Constant • Expression • Statement • Modify-And-Assign • Math Class

41. Statement Statement#1 Statement#2 Statements 42 • A statement is a unit of command to instruct your program • A method consists of one or more statements class Hello { static void Main () { Console.WriteLine("Hello World!"); Console.ReadLine(); } }

42. C# Statement Types Statement Assignment Statement Input Statement Output Statement C# Statement Types 43

43. Statement Assignment Statement 44 • Assigning value to variable • Use the equal sign (=) when making assignments. • Syntax: • <variable> = <expression>; int Width,High; Width=10; High=20+Width;

44. Statement Input Statement 45 • Console.ReadLine() Return string • Use to get the input from user • Convert string to other data type • int.Parse() • Convert string to integer • double.Parse() • Convert string to double Example string st; st = Console.ReadLine();

45. Statement Example: Input Statement 46 • Ex1: • string myname; • myname = Console.ReadLine(); Ex2: int Width; string temp1; temp1 = Console.ReadLine(); Width = int.Parse(temp1);

46. Statement Output Statements 47 • Use the method Write or WriteLine in the Console class (which is in System namespace) • Basic usage: • Advanced usage: • Even more advanced usage: Console.WriteLine("Hello"); Console.WriteLine(area); Console.WriteLine(”Size {0}x{1}”, width, height); double salary=12000; Console.WriteLine("My salary is {0:f2}.", salary);

47. Outline 48 • C# Beginning • Variable and Constant • Expression • Statement • Math Class

48. Math Class The Math Class 49

49. Test III 50 • Write the program which • Input : Your name • Output : Your name is <your name>.

50. Test IV 51 • Write the program which • Input : 3 number • Output : average of 3 input number