Introduction to C# Language - Nakov

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XML C# Anders Hejlsberg, Delphi -o , , XML- header , IDL ,

5.ToString() C#

(code access security role-based security) ECMA ISO C# ,

Main() , (namespaces) namespace C# HelloCSharp.cs using System; class HelloCSharp { static void Main() { Console.WriteLine("Hello, C#"); } } Java

C++ ? using System; class static void Main()

#include C++ import Java uses Delphi , System.Console #1 csc HelloCSharp.cs HelloCSharp.exe

Hello, C# #2 , Visual Studio.NET FrameworkNET [Ctrl+F5] C# abstract as base bool break byte case

catch char checked class const continue decimal default delegate do double else enum

event explicit extern false finally fixed float for foreach goto if implici t in

int interfac e interna l is lock long namespace new null object operato r

out override params private protecte d public readonl y ref return sbyte sealed short

sizeof stackallo c static string struct switch this throw true try C#

(value types) (reference types) - () garbage collector- o

(, built-in) C# (value types) int i; enum State { Off, On } struct Point { int x, y; } (reference types)

class Foo: Bar, IFoo {...} interface IFoo: IBar {...} string[] a = new string[5]; delegate void Empty(); C# CTS .NET FrameworkNET Framework int = System.Int32 C# (built-in data types)

C C++ byte, sbyte, int, uint, long, ulong float, double, decimal char Unicode bool (true false) string Unicode object

(implicit conversion) , : int long, float double, long float, byte short (explicit conversion) - long int, double float, char short, int char, sbyte uint

checked System.OverflowException byte b8 = 255; short sh16 = b8; // implicit conversion int i32 = sh16; // implicit conversion float f = i32; // implicit - possible loss of precision! double d = f; // implicit conversion checked { byte byte8 = (byte) sh16; // explicit conversion // OverflowException is possible! ushort ush16 = (ushort) sh16; // explicit conversion // OverflowException is possible if sh16 is negative! } unchecked { uint ui32 = 1234567890; sbyte sb8 = (sbyte) ui32; // explicit conversion // OverflowException is not thrown in unchecked mode } (enumerations)

C# enum.NET Framework : enum Days {Sat, Sun, Mon, Tue, Wed, Thu, Fri}; int, int (enumerations) System.Enum

[Flags] [Flags] public enum FileAccess { Read = 1, Write = 2, Execute = 4, ReadWrite = Read | Write } //... Console.WriteLine( FileAccess.ReadWrite | FileAccess.Execute); // The result is: "ReadWrite, Execute" , Unicode

int _ = 118; bool \u1027\u11af = true; Microsoft PascalCase , namespace-, , , , , camelCase C# ( C++, Java Delphi):

( ) - int count; public static int mCounter; compile-time const runtime readonly

C# : Compile-time : public const double PI = 3.1415926535897932; const string COMPANY_NAME = " "; " ";; const

C# : Run-time public readonly DateTime NOW = DateTime.Now; readonly , ( )

C++ Java, : +, -, *, /, %, ++, -: &&, ||, !, ^, true, false : &, |, ^, ~, <<, >> : + : ==, !=, <, >, <=, >= : =, +=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>= : as, is, sizeof, typeof : ., [], (), ?:, new, checked, unchecked, unsafe (expressions) ,

expressions C++ Java : a = b = c = 20; // 20 (+5)*(32-a)%b // " ";" "; + " ";" "; // (stringstring) Math.Cos(Math.PI/x) // typeof(obj) // System.Type (int) arr[idx1][idx2] // int new Student() // Student (currentValue <= MAX_VALUE) // (statements) (statements) C++ Java : { }

(.NET Framework lock) (statements) - .NET Framework : sum = (a+b)/2; // (string<> = <>) PrintReport(report); // student = new Student(" ";

" ";, 3, 42688); // { } , .NET Framework : Report report = GenerateReport(period); report.Print(); (conditional statements) if if-else

if (orderItem.Ammount > ammountInStock) { MessageBox.Show(" ";Not in stock!" ";, " ";error" ";); } if (Valid(order)) { ProcessOrder(order); } else { MessageBox.Show(" ";Invalid order!" ";, " ";error" ";); } (conditional statements) switch case string enum switch (characterCase) {

case CharacterCasing.Lower: text = text.ToLower(); break; case CharacterCasing.Upper: text = text.ToUpper(); break; default: MessageBox.Show(" ";Invalid case!" ";, " ";error" ";); ); break; } (iteration statements) for- // 1 100 for (int i=1; i<=100; i++) { int i2 = i*i; Console.WriteLine(i + " "; * " "; + i + " "; = " "; + i2); }

while- // result = a^b result = 1; while (b > 0) { result = result * a; b--; } (iteration statements) do-while // do { ch = ReadNextCharacter(stream); }

while (ch != '\n'); foreach string[] names = GetNames(); // foreach (string name in names) { Console.WriteLine(name); } break, continue goto return // target a[]

int position = -1; for (int i=0; i

try-finally try-catch-finally lock checked, unchecked fixed #3 , 25 Digits.cs using System; public class Digits { static void Main()

{ for (int d1=1; d1<=9; d1++) for (int d2=0; d2<=9; d2++) { int d3 = 25 - d1 - d2; if ((d3 >= 0) && (d3 <= 9)) { int n = d1*100 + d2*10 + d3; Console.WriteLine(n); } } } } #4 VS.NET FrameworkNET #5 ILDASM ILDASM Digits.exe

Order orders[]; // /* , . , Deleted */ foreach (Order order in customer.rders) { if (!AllItemsInStock(order)) { order.Status = OrderStatus.Deleted; } } XML

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