Shildt Gerbert - Polny Spravochnik Po C

: 3 !

, , C#.- , C# , Microsoft

INTER

NET

OsborneMcGrawHill

32.973.26-018.2.75 57

681.3.07

. ..

..

:

[email protected], http://www.williamspublishing.com , .

57 C#. : . . . : , 2004. 752 . : . . . .

ISBN 5-8459-0563- (.)

C# ,

.NET, : , , , , , , , , . C#.

C C++, Java C# , , . , C#.

32.973.26-018.2.75

.

, , , Osborne Publishing.

Authorized translation from the English language edition published by McGraw-Hill Companies, Copyright 2003

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage retrieval system, without permission from the Publisher.

Russian language edition published by Williams Publishing House according to the Agreement with R&I Enterprises International, Copyright 2004

ISBN 5-8459-0563- (.) ISBN 0-07-213485-2 (.)

, 2004 by The McGraw-Hill Companies, 2003

18 I. C# 21 1. C# 22 2. C# 30 3. , 53 4. 80 5. 102 6. , 126 7. 154 8. 179 9. 224 10. 256 11. 277 12. , 319 13. 349 14. - 375 15. 409 16. , 431 17. , 449 18. , 484 II. C# 501 19. System 502 20. 541 21. 575 22. 610 23. Internet 645 III. C# 669 24. 670 25. Windows- 689 26. 707 IV. 731 . XML 732 . C# 737 740

6

17 18 I. C# 21 1. C# 22

C# 23 C, 23 C++ 24 Internet Java 25 C# 26

C# .NET Framework 27 .NET Framework 27

CLR 28 28

29 2. C# 30

- 31 32 32 33

33 csc.exe 34

34 34 35

Visual Studio IDE 35 , 38

40 41 42 44 45

if 45 for 47

48 50 50

C# 51 51 C# 52

3. , 53 54 C# 54 55 57 decimal 58 60

7

bool 61 62 65

65 66 66

68 68 69

70 72

73 74

76 78

4. 80 81

82 84

87 89

89 90

, , 90 96 99

? 99 101 101

5. 102 if 103

if- 104 if-else-if 105

switch 106 switch 110

for 110 for 112

112 114 115

116 116 for 117

while 117 do-while 119 foreach 120 break 120 continue 122 return 123 goto 123

6. , 126 127

127

8

128 132 133 134

Building 134 137 138 140 Building 142 144

144 146 Building 146

new 147 new 148

149 149

this 151 7. 154

155 155 157 158

159 159 160 161

162 164 Length 165

Length 167 foreach 168 172

172 173 175 177 switch- 178

8. 179 180

C# 180 public private 182 : 182

187 189

ref- out- 191 ref 191 out 193 ref out 195

197 199

9

202 203 208

this 212 Main() 213

Main() 213 Main() 213

215 static 218

223 9. 224

225 226 228

C#- 232 236 true false 237 240 240 , 242 246 250 251

10. 256 257

257 260 263 264

266 271

271 11. 277

278 281

283 285

286 290

base 291 293 296 297 301

305 305

309 sealed 313 object 313

315 object 317

10

12. , 319 320

321 325 327 328 330 331 331

332 333

334 .NET Framework 334 : 335 340

343 345

347 347 347

13. 349 System.Exception 350 350

try- catch- 351 351 353

354 356 catch- 357 358 try- 358 360

360 finally 362 363

365 367 370 checked unchecked 372

14. - 375 C#- - 376

376 376

377 Stream 377 378 378 380

- 380 380 382

FileStream - 383

11

383 FileStream 385 386 FileStream 387

- 389 StreamWriter 389 Stream Reader 391

392 394

BinaryWriter 394 BinaryReader 395 - 396

400 MemoryStream 402 StringReader StringWriter 404 405

15. 409 410

413 System. Delegate 415 416

416 418 , 419 421 425

.NET Framework 426 EventHandler 428

: 429 16. , 431

432 432

434 using 436 using 437 438 440 441 441

#define 442 #if #endif 442 #else #elif 444 #undef 445 #error 446 #warning 446 #line 446 #region #endregion 447

internal 447 internal 447

17. , 449 450

is 450

12

as 451 typeof 453

454 : System.Type 454

455 455

GetMethods() 458 459 462 466 471

474 474

474 475 475

477 480

Attribute Usage 480 Conditional 481 Obsolete 482

18. , 484 485

486 486 * & 487

unsafe 487 fixed 488 489 489 491 492

492 494 494 495

496 sizeof 496 lock 496 readonly 496 stackalloc 497 using 498 const volatile 499

II. C# 501 19. System 502

System 503 Math 504 509

510 511

13

Decimal 514 Char 518 Boolean 523

Array 523 524 526 527

BitConverter 532 Random 534 GC 536 Object 537 IComparable 537 IConvertible 538 ICloneable 538 IFormatProvider IFormattable 540

20. 541 C# 542 String 542

String 543 , String 543 String 544 String 544

544 547

549 552

555 , 556 557 Substring() 558

558 559 560

String.Format() ToString() 561

String.Format() 562 ToString() 564

565 - 565

569 571

573 21. 575

576 Thread 577

577 580 581

, 583 IsBackground 585 586 588

592

14

593 Monitor lock 594

Wait(), Pulse() PulseAll() 594 Wait() Pulse() 595 598

MethodImplAttribute 599 , 601

Abort() 603 Abort() 604

606 606 608 608

22. 610 611

612 ICollection 612 IList 613 IDictionary 614 IEnumerable, IEnumerator IDictionaryEnumerator 615 IComparer 615 IHashCodeProvider 616

DictionaryEntry 616 616

ArrayList 617 ArrayList- 621 622

Hashtable 623 SortedList 625 Stack 629 Queue 631

BitArray 633 636 636

637 IDictionaryEnumerator 638

, 639 IComparable 641 IComparer 642

644 23. Internet 645

System.Net 646 647 Internet- 647

WebRequest 648 WebResponse 650 HttpWebRequest HttpWebResponse 650 650

653 , Create() 653 , GetResponse() 654

15

, GetResponseStream() 654 654

URI 656 HTTP- 657

658 cookie- 659 LastModified 660

: MiniCrawler 661 WebClient 665

III. C# 669 24. 670

671 671

C#- 672 672 C#- COM- 672

IComponent 673 Component 673 674

CipherLib 675 , CipherComp 676

Dispose() 677 Dispose(bool) 678 683

using 684 685

686 688

25. Windows- 689 Windows- 690 Windows-, 691 Windows 691 Windows- 692

Form 692 Windows-, 692

Windows- 694 694 (IDE) 695

695 696 696 696

697 699

700 702 706

26. 707 708 : 709

16

710 711 713

719 720 728 728

IV. 731 . XML 732

XML 733 XML- 734 XML- 734

. C# 737 740

(Herbert Schildt)

, , C++, Java C#. 3 . . , , C++, C++: A Beginner's Guide, C++ from the Ground Up, Java 2: A Beginner's Guide Windows 2000 Programming from the Ground Up. ( . ). : (217) 586-4683.

18

, - :

, . , , , . , - . . , . , (, , ) . , : . C#.

Microsoft .NET Framework, C# . (Anders Hejlsberg). C# : C C++. C , . , C++. , C# : Java. , , C# Java . , , .

, , C# , . , C# , (), , . , ; , COM (Component Object Model Microsoft , , ). . Java C# , . , Java, C# . , C# C++ Java, (type checking) (template class). , C# , ( ).

, . C# . , C# . , .

19

C# .

C# , C# . , .

I, C#. II, C#. III, C#. I C#.

, , , , - , .

II C#. .NET Framework. . .NET Framework , II , System. C#. , , . , C#.

III C#. 24 , 25 Windows- Windows Forms. 26 (recursive descent parser),

.

C++ Java, C# , C# . , C#, , .

,

Visual Studio .Net 7 ( ), .NET Framework.

- Web-

, , Web- : www.osborne.com.

20

C# ,

. , .

C# C#: A Beginner's Guide. , C++, : C++: A Beginner's Guide C++ Teach Yourself C++ C++ from the Ground Up STL Programming from the Ground Up The C/C++ Programming Annotated Archives , Java,

: Java 2: A Beginner's Guide Java Java 2: Programmer's Reference ,

, Teach Yourself

, , .

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. , Web- . , , , , .

, , . . :

E-mail WWW

[email protected] http://www.williamspublishing.com

: 115419, , / 783 03150, , / 152

I C#

I C#. , . , C# (, - ), C#.

1. C# 23

C# . ,

. , , C# .

C# ( Microsoft .NET Framework) . C# , Windows, Internet, . C# .

C# , , . C# .NET Framework.

C#

. ,

. , , . . C#.

C# . (C C++) Java. C#. C# .

, .

(Dennis Ritchie) 1970- PDP-11 DEC (Digital Equipment Corporation), UNIX. , Pascal, , C .

C 1960- . , - (spaghetti code) goto. . , . .

24 I. C#

, C , , , . , ( ), . , , , , , . 1980- .

C . .

, . , , , 5 000.

C++ 1970- ,

C . , . - (). , , . , C, , . - C C++.

C++ (Bjarne Stroustrup) Bell Laboratories ( , -), 1979-. C , 1983 C++. C++ . , C , C++. , , - . , C++ - C. C++ , . , - , - .

1980- C++ 1990- . , . C++ - .

, C++ . . ( ) , .

1. C# 25

Internet Java

Java, Oak ( . ). 1991 Sun Microsystems. Java (James Gosling). (Patrick Naughton), (Chris Warth), (Ed Frank) (Mike Sheridan).

Java - , C++. Java ( ), . Internet , . , , , , . Internet, , . , Java,

, , Java ( ) ( ) , Java Internet, , . 1993 , , , Internet. Internet , . , , .. Internet.

Java , - (bytecode), .. - , Java-. - Java (Java Virtual Machine JVM) . , Java- , JVM. JVM , .

Java- - - C++-, . . , /C++- , , . , /C++-, , () . . , Java- . C#.

26 I. C#

, Java C C++. , C++. Java- C C++ , , , C/C++- Java. , Java ( ), . C++, Java . , Java , C C++ .

C# Java ,

Internet, . (cross-language interoperability) , (mixed-language programming). , , . (), , , .

, Java Windows. Java- Windows ( Java), Java Windows . Windows , Windows Java.

, Microsoft C#, C# 1990- .NET- Microsoft. - 2000 . C# (Anders Hejlsberg) , . , 1980- Turbo Pascal, .

C# C, C++ Java. . . , C C++, Java. C# , , . , .

C# . 1.1. C# . C C# , . , C# , C++. C C++, C# .

C# Java . , Java C C++. . Java C# . C# Java. C# Java , ,

1. C# 27

. Java, C#. , Java, , C#, Java.

. 1.1. C#

C# , .

. C# - . , C# , : , . - .

C# .NET Framework

C# ,

.NET Framework. . -, C# Microsoft , .NET Framework. -, , C#. C# .NET Framework, , .NET Framework , C#.

.NET Framework .NET Framework

, . , Windows. , .NET Framework Windows, .. , , , Windows.

.NET Framework C# . , Common Language Runtime (CLR), , . CLR .NET Framework, , .

, .NET-, . , -, , - , .NET-

C

C++

Java C#

28 I. C#

. , . , : - , . , .NET- , (.. ), .NET-. C# .NET- , C#- .NET-.

CLR

CLR .NET-. .

C#- , , , Microsoft (Microsoft Intermediate Language MSIL). MSIL , . , MSIL . MSIL - Java, .

CLR- . , , MSIL-, , CLR-. .NET Framework .

, Microsoft, JI-. JIT . just-in-time, ( ). . .NET- CLR- JIT-, MSIL- , . , C#- , , MSIL-. , , , MSIL-.

MSIL- (metadata). , , . , MSIL-.

,

(managed code). CLR-. , . , -,

1. C# 29

, MSIL-, CLR-, , -, .NET Framework. , , , .

? Windows- .NET Framework , CLR-. , C#- .

,

CLR-, , , (Common Language Specification CLS). , . CLS- , , . CLS- (Common Type System CTS). CTS- . , C# CLS-, CTS-.

30 I. C#

2 C#

2. C# 31

, , , .

, , . C# . . C#, C#-, . , C#-. I.

-

C# -

(). - C#, C#- - . , , .

, . , , . , ( ) . , . , , . (, FORTRAN COBOL), . , .

, . , , , - , . - . , , . , - .

- . . , : (.. , , ), (.. , ). . , .

32 I. C#

- -. , : . - , . , , .

- -, C#, : , .

, ()

, , . - , . . . , , .

, . . , , . , ( , ) . , .

C# . . , , . C# . . , , , .

, , . , , (instance variable), , , - (member method), . , C# . C C++, , , , , C#- , C/C++- . C# C++, , C#-.

( polymorphism, )

, . . () , . , : , . , . , , , , , , .

2. C# 33

. , , (stack), .. , . , , . , , . , . - , . C# , . , , , .

: . , . , . ( ) () . . .

,

. . () . , , , . , (, .), . , (, .), . , ( , .). , .

, . , , () . , .

C#-.

/* C#-. Example.cs. */

34 I. C#

using System; class Example { // C#- Main(). public static void Main() { Console.WriteLine(" C#-."); } }

C#- Visual Studio .NET. , C#-, : csc.exe (Integrated Development Environment IDE). . ( , , .)

csc.exe , ,

Visual Studio, C#- , . C#- .

1. , . 2. . 3. .

, , Web-

Osborne : www.osborne.com. . - , Notepad. , , , , C#-. , Example.cs.

, C#-, csc.exe, . C:\>csc Example.cs

csc Example.exe, MSIL- . MSIL- , -. Example. Common Language Runtime JIT-. : Example. ( -, MSIL-) , .NET Framework, CLR.

2. C# 35

csc. , , vcvars32.bat, //Program Files/Microsoft Visual Studio.NET/Vc7/Bin. . C# Microsoft Visual Studio .NET , Visual Studio .NET Command Prompt , Visual Studio .NET Tools , , .

.

C:\>Example :

C#-. Visual Studio IDE

7 Visual Studio .NET, Visual Studio IDE C#-. , C#- Visual Studio ( 7), . ( Visual Studio, , .)

1. () C#-, File , New , Project ( , ,).

2. ( Project Types ( )) Visual C# Projects ( Visual C#), ( . 2.1) Templates () Empty Project ( ).

. 2.1. New Project ( )

36 I. C#

3. , Solution Explorer ( ) , , Add , Add New Item ( , ) , 2.2.

4. Add New Item ( ) Categories () Local Project Items ( ), Templates Code File ( ) , 2.3.

2.2. Add , Add New Item

2.3. Add New Item

2. C# 37

5. Example.cs. (, , , Web- Osborne : www.osborne.com.) , . 2.4.

. 2.4. Example.cs

6. Build , Build Solution ( , ).

7. Debug , Start Without Debugging ( , ).

, . 2.5.

. 2.5.

, , . C#-. . .

, ( ) , , , , .

38 I. C#

, , Example.cs

, C#-. , .

(, Java), , C#- . Example.cs, , , Sample.cs, Test.cs X.cs.

C#- .cs, . , . ( , , ) Example.cs. C#- , . , .

. /* C#-. Example.cs. */

. C# , . , , , . Example.cs. , .

C# . , , . /* , (*/). , , . , , .

. using System;

, System. C# (namespace) . , , . , , , , . System, , .NET Framework, C#.

2. C# 39

using , .

. class,

. , C# . Example . ({) (}) . , , , . , , C# . , C#- -.

. // C#- Main().

, C#. // . , , () .

. public static void Main() {

Main(). , C# (method). , . C#- Main(). ( : /C++- main().) , C#. , .

public (access specifier). , . public, , , , . ( public private, , () .) Main() public-, ( ) ( ).

C# , Main() public-. , Visual Studio .NET. C#-. Main() public. , Main().

static Main()

. ,

40 I. C#

Main() . void , Main() . , . Main() , . , Main() ( ) , . ((), Main(). , .

. , Main(). Console.WriteLine(" C#-.");

C#-. . WriteLine(). , . . , WriteLine() . Console , - . Console WriteLine(), , WriteLine() Console. , C# , - .

, , WriteLine(), , using System. C# . , , , .

(}) Main(), Example.

. C# . . , Main main WriteLine writeline, . , C#- , Main(), . , Main (main), . , , Example.exe .

, (

). . , (). C#- - , . , , . ,

2. C# 41

Main(), IDE , 2.6. (

csc)

. 2.6. , ,

, . ,

, . , , , . , , . .

using System; , . , . , C# , . , Console.WriteLine(" C#-."); System.Console.WriteLine(" C#-.");

, // using System. class Example { // C#- Main(). public static void Main() { // Console.WriteLine . System.Console.WriteLine(" C#-. "); } }

42 I. C#

System , , C#- using System ( , ). , , , .

,

. , . . , , .

x y. // . using System; class Example2 { public static void Main() { int x; // . int y; // . x = 100; // x 100. Console.WriteLine("x " + x); y = x / 2; Console.Write("y x / 2: "); Console.WriteLine(y); } }

: x 100 y x / 2: 50

? , int x; // . x . C# . , . . x , .. . C# int. , int x; x int.

y. int y; // .

, , . .

, , :

2. C# 43

_; ,

_ . int, C# .

x 100. x = 100; // x 100.

C# (=). , , , .

x, x . Console.WriteLine("x " + x);

, x. , +, WriteLine() .

y x, 2. y = x / 2;

x 2, y. , y 50. x . , C# , :

+ - * /

: Console.Write("y x / 2: "); Console.WriteLine(y);

. -, "y x/2: " WriteLine(), Write(). B . , . , Write() WriteLine(), , . -, , WriteLine() y , .. . , WriteLine(), Write() C#-,

, . . , x y : int x, y; // .

44 I. C#

int. int . , . , int- 18, 18,3. , int , C#. C# , float double, , . ( double .)

double , : double result;

result - double. result double, , 122,23, 0,034 -19,0.

int double, :

/* int double. */ using System; class Example3 { public static void Main() { int ivar; // int. double dvar; // double. ivar = 100; // ivar // 100. dvar = 100.0; // dvar // 100.0. Console.WriteLine( " ivar: " + ivar); Console.WriteLine( " dvar: " + dvar); Console.WriteLine(); // . // 3. ivar = ivar / 3; dvar = dvar / 3.0; Console.WriteLine("ivar : " + ivar); Console.WriteLine("dvar : " + dvar); } }

: ivar: 100 dvar: 100

2. C# 45

ivar : 33 dvar : 33.3333333333333

, ivar 3 , 33, .. . dvar 3 .

, , . , . , C# 100 , 100.0 .

, WriteLine .

, .. . , , 3,1416. // . using System; class Circle { static void Main() { double radius; double area; radius = 10.0; area = radius * radius * 3.1416; Console.WriteLine(" " + area); } }

- : 314.16

, .

, ,

. , C#. , , , .

if if

. if C# . C, C++ Java, . : if() ;

46 I. C#

( ), , . ( ) . : if(10 < 11) Console.WriteLine("10 11");

10 11, .. , WriteLine() . : if(10 < 9) Console.WriteLine(" .");

10 9, WriteLine() .

C# , . :

< >= == !=

if. // if. using System; class IfDemo { public static void Main() { int a, b, c; a = 2; b = 3; if(a < b) Console.WriteLine(" b"); // . if(a == b) Console.WriteLine( " ."); Console.WriteLine(); c = a - b; // c -1. Console.WriteLine("c -1"); if(c >= 0) Console.WriteLine( " c "); if(c < 0) Console.WriteLine(" c "); Console.WriteLine(); c = b - a; // c 1. Console.WriteLine("c 1"); if(c >= 0) Console.WriteLine( " c "); if(c < 0) Console.WriteLine(" c "); } }

2. C# 47

: b c -1 c c 1 c

. int a, b, c; , . , , .

for ,

. C# . for. C, C++ Java, , for C# , . for .

for(; ; ) ;

. , . , for , . , , . , for. // for. using System; class ForDemo { public static void Main() { int count; for(count = 0; count < 5; count = count+1) Console.WriteLine(" : " + count); Console.WriteLine("!"); } }

: : 0 : 1 : 2 : 3 : 4 !

48 I. C#

count. for . ( ) count < 5. , WriteLine(), . , , , .

, C#-, , , . , , : count = count + 1;

, C# , . (++). : count++;

, for : for(count = 0; count < 5; count++)

, , , .

C# (--). , .

, , C#

. . . , , . , , if- for-. if-: if(w < h) { v = w * h; w = 0; }

w h, , w < h, . , , . , , , . .

, . // .

2. C# 49

using System; class BlockDemo { public static void Main() { int i, j, d; i = 5; j = 10; // if- // , . if(i != 0) { Console.WriteLine("i "); d = j / i; Console.WriteLine("j / i " + d); } } }

: i j / i 2

if- , . if- ( ), , . . i = 5; i = 0; .

. 1 10 . // 1 10. using System; class ProdSum { static void Main() { int prod; int sum; int i; sum = 0; prod = 1; for(i=1; i

50 I. C#

55 3628800

( ) , . for-.

. . , ({ }) . , , .

C# , ..

. , ,

. , ( ).

C# ; , . , C# x = y; y = y + 1; Console.WriteLine(x + " " + y); . x = y; y = y + 1; Console.WriteLine(x + " " + y);

, . , . Console.WriteLine(" " + x + y + z + " , ");

.

, , , ,

. C# , , .. , . , . , , , . , ( ), ( ). , .

2. C# 51

C# C# 77 ,

. 2.1. ( ) C#. , .

2.1. C#

abstract event new structas explicit null switch base extern object this bool false operator throw break finally out true byte fixed override try case float params typeof catch for private uint char foreach protected ulong checked goto public unchecked class if readonly unsafe const implicit ref ushort continue in return using decimal int sbyte virtual default interface sealed volatile delegate internal short void do is sizeof while double lock stackalloc else long static enum namespace string

C# , , , . . . , . , line_count. C# , .. myvar MyVar . .

Test x 2 MaxLoad up _top my_var sample23

, . , 12 . , , , .

52 I. C#

C# , , @. , @fr C#-. , - for, @ . , @-. // @-. using System; class IdTest { static void Main() { int @if; // if . for(@if = 0; @if < 10; @if++) Console.WriteLine("@if " + @if); } }

, @if . @if 0 @if 1 @if 2 @if 3 @if 4 @if 5 @if 6 @if 7 @if 8 @if 9

( ) @- . , @ ( ), .

C#

, ,

C#- WriteLine() Write(). , Console, System, .NET Framework. , C#- .NET Framework, -, , (GUIs). , C# C# ( ) .NET-. , C#-. C#-, . I .NET-, .NET- II.

54 I. C#

C#: , . , . C#

, . , C# .

C# , C#

. , . . , . , , . , , . , , . , , .

C#

C# :

. , . C# 13 , . 3.1. , C# C#-.

, . ( : .) , C# , (, C++). .

C# . , C# . , int . . , , .

3.1. C# bool , , / byte 8- char decimal double C

3. , 55

3.1. float int long sbyte 8- short uint ulong ushort

C# : char, byte, sbyte, short,

ushort, int, uint, long ulong. char ( ). . . 3.2.

3.2. byte 8 0 255 sbyte 8 -128 127 short 16 -32 768 32 767 ushort 16 0 65 535 int 32 -2 147 483 648 2 147 483 647 uint 32 0 4 294 967 295 long 64 -9 223 372 036 854 775 808 9 223 372 036 854 775 807 ulong 64 0 18 446 744 073 709 551 615

, C# :

, . . , , , (sign flag). , , , 1, . . , , , . , .

, , ( ) . , 32 767 short:

01111111 11111111

56 I. C#

1, -1 ( ). , ushort ( ), 65 535.

, int. int , . , , int, . , uint ( ). , , long, ulong. , , , . , long. // . using System; class Inches { public static void Main() { long inches; long miles; miles = 93000000; // 93 000 000 //5280 , 12 inches = miles*5280* 12; Console.WriteLine(" : " + inches + " ."); } }

: : 5892480000000 .

, int uint.

byte sbyte. byte 0 255. byte , , . sbyte. byte for, 1 100. // byte. using System; class Use_byte { public static void Main() { byte x; int sum;

3. , 57

sum = 0; for(x = 1; x

58 I. C#

, Sqrt(): Math. , , , Sqrt() Math. ( WriteLine() Console.) , .

, C#. double. , ( ) 0,1 1,0. // Math.Sin(), // Math.Cos() Math.Tan(). using System; class Trigonometry { public static void Main() { double theta; // . for(theta = 0.1; theta

3. , 59

128 . . decimal, 28 ( 29). .

, decimal . // decimal . using System; class UseDecimal { public static void Main() { decimal price; decimal discount; decimal discounted_price; // . price = 19.95m; discount = 0.15m; // 15%. discounted_price = price - (price * discount); Console.WriteLine(" : $" + discounted_price); } }

: : $16,9575

, decimal- m. , decimal. decimal (, 10) m. ( .)

decimal. , . /* decimal . */ using System; class FutVal { public static void Main() { decimal amount; decimal rate_of_return; int years, i; amount = 1000.0M; rate_of_return = 0.07M; years = 10;

60 I. C#

Console.WriteLine(" : $" + amount); Console.WriteLine(" : " + rate_of_return); Console.WriteLine(" " + years + " "); for(i = 0; i < years; i++) amount = amount + (amount * rate_of_return); Console.WriteLine(" $" + amount); } }

: : $1000 : 0,07 10 $1967,15135728956532249

( ) ! , , .

C# 8- ,

(, C++), 16-. C# Unicode (), 16- , . (, , , ) , (, ), , . , 16- . , C# char 16- , 065 535. 8- ASCII Unicode 0127. , ASCII- C#-.

, . , X ch, : char ch; ch = 'X';

char-, ch, WriteLine() Console.WriteLine(" ch: " + ch);

char C# , . , char . , . char ch; ch = 10; // , .

10 , char. . , .

3. , 61

bool

bool /, C#

true false. , bool . C# bool . , 1 true, 0 false.

bool : // bool. using System; class BoolDemo { public static void Main() { bool b; b = false; Console.WriteLine("b " + b); b = true; Console.WriteLine("b " + b); // bool if-. if(b) Console.WriteLine(" ."); b = false; if(b) Console.WriteLine( " ."); // bool. Console.WriteLine("10 > 9 " + (10 > 9)); } }

: b False b True . 10 > 9 True

, ? -, bool- WriteLine() True False. -, bool- if-, .. if- . if(b == true)...

-, (, 9 True. 10 > 9, , , + , >.

62 I. C#

WriteLine() , C#. C# , . , - , . , , . , , C#.

. : Console.WriteLine( " " + 2 + " $" + 3 + " .");

, . , , . : Console.WriteLine( " 10/3 : " + 10.0/3.0);

: 10/3 : 3,33333333333333

, , . , .

WriteLine(), . WriteLine("_", arg0, arg1, ... , argN);

WriteLine() , +. _ : . , , . : {_, : }

_ ( ). , .

WriteLine() , ( ) , _. , _ , , . . , {0} arg0, {1} arg1 ..

.

3. , 63

Console.WriteLine(" {0} {1} .", 28, 29); : 28 29 .

, {0} 28, {1} 29. , ( 28 29). , +, .

, . Console.WriteLine( " {0,10} {1,5} .", 28, 29);

: 28 29 .

, , . , . , .

, , , . , . // . using System; class DisplayOptions { public static void Main() { int i; Console.WriteLine("\t\t"); for(i = 1; i < 10; i++) Console.WriteLine("{0}\t{1}\t{2}", i, i*i, i*i*i); } }

: 1 1 1 2 4 8 3 9 27 4 16 64 5 25 125 6 36 216 7 49 343 8 64 512 9 81 729

. , . . , WriteLine(). #, .

64 I. C#

, . 10 3. . Console.WriteLine( " 10/3 : {0:#.##}", 10.0/3.0);

-: 10/3 : 3.33

#.##, WriteLine() . , , , .

. Console.WriteLine("{0:###,###.##}", 123456.56); : 123,456.56

, . : decimal balance; balance = 12323.09m; Console.WriteLine(" {0:C}, balance);

: $12,323.09

, . /* C . */ using System; class UseDecimal { public static void Main() { decimal price; decimal discount; decimal discounted_price; // . price = 19.95m; discount = 0.15m; // 15%. discounted_price = price - (price * discount); Console.WriteLine(" : {0:C}", discounted_price); } }

, , : : 16,96.

3. , 65

C# ,

. , 100 . . , . .

C#- . . , . , , % .

. , 10 -100 . , . 11.123. C# ( ).

C# , . : ? , , 12, 123987 0.23? , C# , .

-, , , , int. , , , int, uint, long ulong. -, double.

, C#, , . long, l L. , 12 int, 12L long. , u U. , 100 int, 100U uint. ul UL (, 987654UL ulong).

float, f F (, 10.19F).

decimal, m (, 9. 95).

int-, uint-, long- ulong- , byte, sbyte, short ushort, , , .

, ,

16, . 0 9 F, 10, 11, 12, 13, 14 15. , 10 16. C#, ,

. 0x ( x). . count = 0xFF; // 255

66 I. C#

incr = 0x1a; // 26

, , (, ), . , , C# , . C# (ESC-), . 3.3. , .

, ch : ch = \t;

ch : ch = \;

3.3.

ESC- \ () \b \f ( ) \n \r \t \v \0 - \ () \" \\

C# : .

, . , " " . ( WriteLine()) .

, . , , . ESC-, \n, \t \". // ESC- . using System;

3. , 67

class StrDemo { public static void Main() { Console.WriteLine( " \n \n "); Console.WriteLine("\t\t"); Console.WriteLine("\t\t"); // . Console.WriteLine("\"?\", ."); } }

: "?", .

, \n , WriteLine() . , , ESC- \n. , ( ESC- \").

(verbatim) . @, , . . , , ., . ("). , (""). , . // . using System; class Verbatim { public static void Main() { Console.WriteLine(@" , . "); Console.WriteLine(@" : 1 2 3 4 5 6 7 8 "); Console.WriteLine( @" : "" C#."""); } }

:

68 I. C#

, : 1 2 3 4 5 6 7 8 : " C#."

, , . , . . , .

. . (, 'X') char. , (, X), - .

2,

: _;

, _ . . . , . , bool . , . , int char.

C# . , , , , . C# .

. , , , , .

.

. . . : _ = ;

3. , 69

, , , . .

: int count = 10; // count // 10. char ch = 'X'; // ch X. float f = 1.2F // f // 1.2.

( ) . , int a, b = 8, c = 19, d; // b c // .

, C# , , . , , , , . // . using System; class DynInit { public static void Main() { double s1 = 4.0, s2 = 5.0; // . // hypot. double hypot = Math.Sqrt((s1 * s1) + (s2 * s2)); Console.Write(" " + s1 + " " + s2 + " "); Console.WriteLine("{0:#.###}.", hypot); } }

: 4 5 6,403.

: s1, s2 hypot. (s1 s2) , , hypot, . , Math.Sqrt(). , , . Math.Sqrt() ( ) , hypot. , , , , .

70 I. C#

, ,

Main(). C# . , . , (scope) . , , , . .

C# , . ( , ) , , , .

, , . , .

, , , (.. ) , . , / . .

. , . . , , , . : , , .

, : // . using System; class ScopeDemo { public static void Main() { int x; // x // Main(). x = 10; if(x == 10) { // . int y = 20; // y // . // x y. Console.WriteLine("x y: " + x + " " + y); x = y * 2; } // y = 100; // ! y . // x . Console.WriteLine(" x " + x); } }

3. , 71

, x Main() . if y. , y . , , // y = 100; //! y . . , , y if-. x if-, (.. ) , .

, . , , . , , , .

, . , . , , , . , , . , .

, , . , , : // . using System; class VarInitDemo { public static void Main() { int x; for(x = 0; x < 3; x++) { int y = -1; // y // Console.WriteLine(" y : " + y); // // -1. y = 100; Console.WriteLine(" y : " + y); } } }

: y : -1 y : 100 y : -1 y : 100 y : -1 y : 100

72 I. C#

, for y 1. 100, .

: , , , , , . , - . /* , , . *** . *** */ using System; class NestVar { public static void Main() { int count; for(count = 0; count < 10; count = count+1) { Console.WriteLine("This is count: " + count); int count; // !!! for(count = 0; count < 2; count++) Console.WriteLine(" !"); } } }

C/C++, , , , . , C/C++ count for . . C#, , , .

. , , float int. int i; float f; i = 10; f = i; //float- int-.

, ( ) . , ,

3. , 73

int- i, float, f. , C# , . , bool int . , - . .

, ; (.. ),

. ,

. , int , byte, int, byte , .

, , . , , long double , . // // long double. using System; class LtoD { public static void Main() { long L; double D; L = 100123285L; D = L; Console.WriteLine("L D: " + L + " " + D); } }

long double, ( double long) , . , : // *** . *** using System; class LtoD { public static void Main() { long L; double D; D = 100123285.0; L = D; // !!!

74 I. C#

Console.WriteLine("L D: " + L + " " + D); } }

decimal float ( double), char ( bool). , char bool.

, . . . : (_)

_ . , , x/y int, : double x, y; // ... (int) (x / y);

, , x y double, int. , x / y, . ( ) int x, . , double int .

, . , long int , long , int, long-. . , 1,23 1. (0,23) .

, , . // . using System; class CastDemo { public static void Main() { double x, y; byte b; int i; char ch; uint u;

3. , 75

short s; long l; x = 10.0; y = 3.0; // double int. i = (int) (x / y); // . Console.WriteLine( " x / y: " + i); Console.WriteLine(); // int byte . i = 255; b = (byte) i; Console.WriteLine("b 255: " + b + " -- ."); // int byte i = 257; b = (byte) i; Console.WriteLine("b 257: " + b + " -- ."); Console.WriteLine(); // uint short . u = 32000; s = (short) u; Console.WriteLine("s 32000: " + s + " -- ."); // uint short . u = 64000; s = (short) u; Console.WriteLine("s 64000: " + s + " -- ."); Console.WriteLine(); // long uint . l = 64000; u = (uint) l; Console.WriteLine("u 64000: " + u + " -- ."); // long uint . l = -12; u = (uint) l; Console.WriteLine("u -12: " + u + " -- ."); Console.WriteLine(); // byte char. b = 88; // ASCII- X. ch = (char) b; Console.WriteLine("ch 88: " + ch); } }

76 I. C#

: x/y: 3 b 255: 255 -- . b 257: 1 -- . s 32000: 32000 -- . s 64000: -1536 -- . u 64000: 64000 -- . u -12: 4294 967284 -- . ch 88: X

. (x / y) int , .. .

, b 255, byte 255. b 257 , 257 byte. , int byte .

s short 32 000 ( u uint) , short- 32 000. , 64 000 short, . , uint short .

u ( uint) 64 000 ( l long). , 64 000 uint-. u -12, , , uint . , long uint .

, byte- char , .. , .

,

. , . , short long, . , .

. .

3. , 77

decimal, TO , .. decimal ( float double, ).

double, TO double.

float, TO float. ulong, TO

ulong ( sbyte, short, int long, ).

long, TO long. uint, sbyte, short int,

long. uint, TO uint. int.

. - . , float double decimal. ulong . - , .

-, . , int, . , char-, sbyte-, byte-, ushort- short- int. int- (integer promotion). , int.

, , . , byte int, - byte. .

. , , byte-. . byte- int, , int. , byte- byte- int-. . : // ! using System; class PromDemo { public static void Main() { byte b;

78 I. C#

b = 10; b = (byte) (b * b); // )!! Console.WriteLine("b: "+ b); } }

, b * b b . , b * b b int, .. b * b int-, byte- . , , , , , .

char. , - char- int . char ch1 = 'a', ch2 = 'b'; ch1 = (char) (ch1 + ch2);

ch1 ch2 int, int- char-.

(, ). , int (.. sbyte-, byte-, short- ushort-), int. To char. , uint- long.

, . . , , . 1 10. . , Math.Sqrt() int. // . using System; class CastExpr { public static void Main() { double n; for(n = 1.0; n

3. , 79

" : {0}", Math.Sqrt(n) - (int) Math.Sqrt(n) ); Console.WriteLine(); } } }

: 1 1 : 1 : 0 2 1,4142135623731 : 1 : 0,414213562373095 3 1,73205080756888 : 1 : 0,732050807568877 4 2 : 2 : 0 5 2,23606797749979 : 2 : 0,23606797749979 6 2,44948974278318 : 2 : 0,449489742783178 7 2,64575131106459 : 2 : 0,645751311064591 8 2,82842712474619 : 2 : 0,82842712474619 9 3 : 3 : 0 10 3,16227766016938 : 3 : 0,16227766016838

, , Math.Sqrt(), int, . ( , ):

Math.Sqrt(n) - (int) Math.Sqrt(n)

double. int Math.Sqrt().

4. 81

C# ,

. C# : , , . ?. C# , , .

C# .

+ - , * / % -- ++

C#- +, -, * /

( , ). .

, , . , (/) . , 10/3 3. (%). , : . , 10 % 3 1. C# % , . , 10,0 % 3,0 1. ( C/C++ .) . // %. using System; class ModDemo { public static void Main() { int iresult, irem; double dresult, drem; iresult =10/3; irem = 10 % 3; dresult = 10.0 / 3.0; drem = 10.0 % 3.0;

82 I. C#

Console.WriteLine( " 10/3: " + iresult + " " + irem); Console.WriteLine( " 10.0 / 3.0: " + dresult + " " + drem); } }

: 10 / 3: 3 1 10.0 / 3.0: 3,33333333333333 1

, % , 1, , .

(++) (--) , . , , .

, 1, 1 . , x = x + 1; : x++;

x = x - 1; : x--;

,

. ,

x = x + 1; ++x; // . : x++; // .

,

: . , . , C# , , . , C# , , . :

x = 10; y = ++x;

4. 83

y 11. , y 10: x = 10; y = x++;

x 11. , 11 ( y ).

. , : /* ++. */ using System; class PrePostDemo { public static void Main() { int x, y; int i; x = 1; Console.WriteLine( ", y = x + x++;"); for(i = 0; i < 10; i++) { y = x + x++; // ++ Console.WriteLine(y + " "); } Console.WriteLine(); x = 1; Console.WriteLine( ", y = x + ++x;"); for(i = 0; i < 10; i++) { y = x + ++x; // ++ Console.WriteLine(y + " "); } Console.WriteLine(); } }

: , y = x + x++; 2 4 6 8 10 12 14

84 I. C#

16 18 20 , y = x + ++x; 3 5 7 9 11 13 15 17 19 21

,

y = x + x++; x x, y. x. y = x + ++x; -. ( ) x, , , y. , x++ ++x , , . . x + ++x; , . , . , x x.

(/)

, . / - , . .

, . == != > < >=

4. 85

. & | ^ && || !

bool. C# (,

== !=) . , , =, , . , . bool , true false . , C# true > false .

, bool, bool. &, |, ^ ! , , .

p q p & q p | q p ^ q !p

false false false false false true true false false true true false false true false true true true true true true true false false

,

, . ,

. // // . using System; class RelLogOps { public static void Main(){ int i, j; bool b1, b2; i = 10; j = 11; if(i < j) Console.WriteLine("i < j"); if(i

86 I. C#

if(i >= j) Console.WriteLine(" ."); if(i > j) Console.WriteLine(" ."); b1 = true; b2 = false; if(b1 & b2) Console.WriteLine(" ."); if(!(b1 & b2)) Console.WriteLine("! (b1 & b2) -- "); if(b1 | b2) Console.WriteLine("b1 | b2 -- "); if(b1 ^ b2) Console.WriteLine("b1 ^ b2 -- "); } }

: i < j i

4. 87

Console.WriteLine( "p " + p + ", q " + q); if(!p | q) Console.WriteLine(" " + p + " " + q + " " + true); Console.WriteLine(); } } } }

: p True, q True True True True p True, q False p False, q True False True True p False, q False False False True

C# (short-circuit) , . , , , , . , , . , . , .

&&, || ( & |, ). , , .

, . , d n. . d / n , , d n. , . // using System; class SCops { public static void Main() { int n, d; n = 10; d = 2; if(d != 0 && (n % d) == 0)

88 I. C#

Console.WriteLine(d + " " + n); d = 0; // d . // d , // . if(d != 0 && (n % d) == 0) Console.WriteLine(d + " " + n); /* . ( ). */ if(d != 0 & (n % d) == 0) Console.WriteLine(d + " -- " + n); } }

, if d . , . , d 2, . ( d ) , , . , , .

, : C# ?. , , , . , : // . using System; class SideEffects { public static void Main() { int i; i = 0; /* i , , . */ if(false & (++i < 100)) Console.WriteLine(" ."); Console.WriteLine( " if : " + i); // : 1 /* i , . */ if(false && (++i < 100)) Console.WriteLine(" ."); Console.WriteLine( " if : " + i); // - 1 !! } }

4. 89

, if- i if-. if- i , false. . /, , , , .

. , .

2.

. (=). C# , . . = ;

. , . , , . int x, y, z; x = y = z = 100;// x, y // z 100.

x, y z 100 . , . , z = 100 100, y, x. ( ) .

C# ,

. . : x = x + 10;

, : x += 10;

+= x x 10. .

x = x - 100; : x -= 100;

x , 100.

90 I. C#

(.. , ). : op = ;

op , .

. += -= *= /= %= &= |= ^=

, .

. -, . -, ( ). .

C# ,

C#. . bool, float double.

, (), . , , . . 4.1.

4.1. & | ^ >>

4. 91

p q p & q p | q p ^ q ~p 0 0 0 0 0 1 1 0 0 1 1 0 0 1 0 1 1 1 1 1 1 1 0 0

. , 0 0 . :

1101 0011 1010 1010 & ________ 1000 0010 &

. ( ) . , 9 0000 1001. 8 (0000 1000 ). // // "" . using System; class MakeEven { public static void Main() { ushort num; ushort i; for(i = 1; i

92 I. C#

num : 4 num: 6 num : 6 num: 7 num : 6 num: 8 num : 8 num: 9 num : 8 num: 10 num : 10

0xFFFE, , 1111 1111 1111 1110. , num & 0xFFFE , . , , , ( ).

. , , . // // , . using System; class IsOdd { public static void Main() { ushort num; num = 10; if((num & 1) == 1) Console.WriteLine(" ."); num = 11; if((num & 1) == 1) Console.WriteLine(num + " -- ."); } }

: 11 -- .

if num 1. num (.. ), num & 1 . . if , .

, &, , byte . .

4. 93

// , . using System; class ShowBits { public static void Main() { int t; byte val; val = 123; for(t = 128; t > 0; t = t/2) { if((val & t) != 0) Console.Write("1 "); if((val & t) == 0) Console.Write("0 "); } } }

: 01111011

for val. , , 1, 0.

, , . , 1, , . :

1101 0011 1010 1010 | ________ 1111 1011

. // // "" . using System; class MakeOdd { public static void Main() { ushort num; ushort i; for(i = 1; i

94 I. C#

: num: 1 num : 1 num: 2 num : 3 num: 3 num : 3 num: 4 num : 5 num: 5 num : 5 num: num : 7 num: 7 num : 7 num: 8 num : 9 num: 9 num : 9 num: 10 num : 11

, for, 1, 0000 0001. , 1 , . , , ( ). , , , , .. .

(XOR) , , .. . :

0111 1111 1011 1001 ^ ________ 1100 0110 XOR ,

. XOR X Y, XOR Y, X. ,

R1 = X ^ Y; R2 = R1 ^ Y; R2 X. ,

XOR, (Y), (X).

4. 95

, , . , . : // XOR // . using System; class Encode { public static void Main() { char ch1 = 'H'; char ch2 = 'i'; char ch3 = '!'; int key = 88; Console.WriteLine(" : " + ch1 + ch2 + ch3); // . ch1 = (char) (ch1 ^ key); ch2 = (char) (ch2 ^ key); ch3 = (char) (ch3 ^ key); Console.WriteLine(" : " + ch1 + ch2 + ch3); // . ch1 = (char) (ch1 ^ key); ch2 = (char) (ch2 ^ key); ch3 = (char) (ch3 ^ key); Console.WriteLine(" : " + ch1 + ch2 + ch3); } }

: : Hi! : >1 : Hi!

, XOR, , () .

( 1) . , ( ), 1001 0110, ~ 0110 1001.

1 . // . using System; class NotDemo { public static void Main() {

96 I. C#

sbyte b = -34; int t; for(t = 128; t > 0; t = t/2) { if((b & t) != 0) Console.Write("1 "); if((b & t) == 0) Console.Write("0 "); } Console.WriteLine(); // . b = (sbyte) ~b; for(t = 128; t > 0; t = t/2) { if((b & t) != 0) Console.Write("1 "); if((b & t) == 0) Console.Write("0 "); } } }

: 11011110 00100001

C# . C# :

> . :

> _.

, _ , .

, , , . , , . , . , . : . , , , .

, . , , .

, . , , , .. 1, 0. . , . val 1, 128, 1000 0000. , , , .

4. 97

// >. using System; class ShiftDemo { public static void Main() { int val = 1; int t; int i; for(i = 0; i < 8; i++) { for(t = 128; t > 0; t = t/2) { if((val & t) != 0) Console.Write("1 "); if((val & t) == 0) Console.Write("0 "); } Console.WriteLine(); val = val 0; t = t/2) { if((val & t) != 0) Console.Write("1 "); if((val & t) == 0) Console.Write("0 "); } Console.WriteLine(); val = val >> 1; // . } } }

: 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1

2, 2. . . , , ( ) . : // // 2.

98 I. C#

using System; class MultDiv { public static void Main() { int n; n = 10; Console.WriteLine(" n: " + n); // 2. n = n 1; Console.WriteLine( " n n = n / 2: " + n); // 4. n = n >> 2; Console.WriteLine( " n n = n / 4: " + n); Console.WriteLine(); // n . n = 10; Console.WriteLine(" n: " + n); // 2, 30 . n = n

4. 99

, int . . , 2. ( , , 3.)

, . , x (XOR) x 127. x = x ^ 127; x ^= 127;

?

C# ?.

? if-then-else. ? , . : 1 ? 2 : 3;

1 bool. 2 3 . .

?- . 1. , 2, ?-. 1 , ?- 3. , absval val. absval = val < 0 ? -val : val; // // val.

absval val, . val , absval , .

?. 100 , . // ? using System; class NoZeroDiv { public static void Main() { int result; int i;

100 I. C#

for(i = -5; i < 6; i++) { result = i != 0 ? 100 / i : 0; if(i != 0) Console.WriteLine("100 / " + i + " " + result); } } }

. 100 / -5 -20 100 / -4 -25 100 / -3 -33 100 / -2 -50 100 / -1 -100 100 / 1 100 100 / 2 50 100 / 3 33 100 / 4 25 100 / 5 20

: result - i != 0 ? 100 / i : 0;

result 100 i. , i . ( i = 0) result .

, ?. , , . . , ?, bool, if. , , , ( ). // ?-. using System; class NoZeroDiv2 { public static void Main() { int i; for(i = -5; i < 6; i++) if(i != 0 ? true : false) Console.WriteLine("100 / " + i + " " + 100 / i); } }

if. i , if- false, , , . ( ) .

4. 101

C# (

). , , : =10/y*(127/x); x = 10 / y * (127/x);

( , ) , . . , , ! ( , , ) . , , ? x = y/3-34*temp+127; X = (y/3) - (34*temp) + 127;

. 4.2 C#- (

). , .

4.2. C#- ( ) [ ] . ++()--() checked new sizeof typeof unchecked ! ~ +() -() ++() --() * / % + - > < >= is == != & ^ | && || ?: = op=

5. 103

C#-. :

(if, switch), ( for-, while-, do-while- foreach-) (break, continue, goto, return throw). throw, C#- ( 13), .

if

if 2,

. : if() ; else ;

C#. else . . if- : if() { } else { }

, , , if-; else- ( ). . , if-, bool.

, if-else- , . // , // . using System; class PosNeg { public static void Main() { int i; for(i=-5; i

104 I. C#

: -5: -4: -3: -2: -1: 0: 1: 2: 3: 4: 5:

, i , if- ( : ); else- ( : ). .

if- if- ,

(. ) if-. if- . , else- if-, , else-. : if(i == 10) { if(j < 20) a = b; if(k > 100) c = d; else a = c; // else- // if(k > 100). } else a = d; // else- if(i == 10).

, else- if(j < 20), ( if- , else-). else- if(k > 100), .

. . , else-, : . // , , // . using System; class PosNegZero { public static void Main() { int i; for(i=-5; i

5. 105

Console.Write(" " + i + ": "); if(i < 0) Console.WriteLine(" "); else if(i == 0) Console.WriteLine(" "); else Console.WriteLine(" "); } } }

: -5: -4: -3: -2: -1: 0: 1: 2: 3: 4: 5: if-else-if

, if-, if-else-if. : if() ; else if() ; else if() ; . . . else ;

. . - , , , . , , else- ( , , ). else- , , .

if-else-if- , { ). // , // . using System;

106 I. C#

class Ladder { public static void Main() { int num; for(num = 2; num < 12; num++) { if((num % 2) == 0) Console.WriteLine(" " + num + " 2."); else if((num % 3) == 0) Console.WriteLine(" " + num + " 3."); else if((num % 5) == 0) Console.WriteLine(" " + num + " 5."); else if((num % 7) ==0) Console.WriteLine(" " + num + " 7."); else Console.WriteLine(num + " 2, 3, 5 7."); } } }

: 2 2. 3 3. 4 2. 5 5. 6 2. 7 7. 8 2. 9 3. 10 2. 11 2, 3, 5 7.

, else- , if-.

switch

switch. switch . . if-, switch . . . , . switch : switch{) { case 1: break; case 2:

5. 107

break; case 3: break; default: break; }

switch (, char, byte, short int) string ( ). , , . switch- ; case- , . case- switch- .

default- , case- switch-. default . , case- . - , , case- , break.

switch- . // switch. using System; class SwitchDemo { public static void Main() { int i; for(i=0; i

108 I. C#

} } }

: i . i . i . i . i . i . i . i . i . i .

, , case-, x. . i , default-.

switch- int. , , switch- , char. case- char- char-. // char // switch-. using System; class SwitchDemo2 { public static void Main() { char ch; for(ch='A'; ch

5. 109

ch C ch D ch E

, default- . , . , .

C# , , case-, , . , , . case- break. ( , goto, , break .) break, case-, switch , switch. default- break.

C# , C++ Java. case- , case-, .. . C# . -, case-, , case- . -, case- , .

case- , , , , case . // "" case- "". using System; class EmptyCasesCanFall { public static void Main() { int i; for(i=1; i < 5; i++) switch(i) { case 1: case 2: case 3: Console.WriteLine("i 1, 2 3"); break; case 4: Console.WriteLine("i 4"); break; } } }

110 I. C#

: i 1, 2 3 i 1, 2 3 i 1, 2 3 i 4

, i 1, 2 3, WriteLine(), i 4, . case- , case- .

case- case-, .

switch switch case-

switch. switch. , case- switch , . , : switch(ch1) { case 'A': Console.WriteLine( " - switch."); switch(ch2) { case 'A': Console.WriteLine( " - switch."); break; case '': // ... } // switch. break; case '': // ...

for

2, for.

, , . . , for : for(; ; ) ;

for , : for(; ; ) { }

, .

5. 111

, . bool, . , for . , , . , for . for , . , , for.

for , , . , 100 -100 , 5. // for // . using System; class DecrFor { public static void Main() { int x; for(x = 100; x > -100; x -= 5) Console.WriteLine(x); } }

, for. , , . : for(count=10; count < 5; count++) x += count; // .

, count . (count < 5) . .

for , . , for 2 20. , . /* . , . */ using System; class FindPrimes { public static void Main() { int num; int i; int factor; bool isprime; for(num = 2; num < 20; num++) {

112 I. C#

isprime = true; factor = 0; // , num i . for(i=2; i

5. 113

public static void Main() { int i, j; for(i=0, j=10; i < j; i++, j--) Console.WriteLine("i j: " + i + " " + j); } }

: i j: 0 10 i j: 1 9 i j: 2 8 i j: 3 7 i j: 4 6

. i j. i , j . . for , .

for. , ( 100). : . /* for . */ using System; class Comma { public static void Main() { int i, j; int smallest, largest; int num; num = 100; smallest = largest = 1; for(i=2, j=num/2; (i = 2); i++, j--) { if((smallest == 1) & ((num % i) == 0)) smallest = i; if((largest == 1) & ((num % j) == 0)) largest = j; } Console.WriteLine(" : " + largest); Console.WriteLine(" : " + smallest); } }

:

114 I. C#

: 50 : 2

for , . i. 2 , ( num). j. , num, , . , i j . .

, for,

, bool. , done. // bool. using System; class forDemo { public static void Main() { int i, j; bool done = false; for(i=0, j=100; !done; i++, j--) { if(i*i >= j) done = true; Console.WriteLine("i, j: " + i + " " + j); } } }

: i, j: 0 100 i, j: 1 99 i, j: 2 98 i, j: 3 97 i, j: 4 96 i, j: 5 95 i, j: 6 94 i, j: 7 93 i, j: 8 92 i, j: 9 91 i, j: 10 90

for , bool- done true. true , i j .

5. 115

C# (, ,

) . . : // for . using System; class Empty { public static void Main() { int i; for(i = 0; i < 10; ) { Console.WriteLine(" " + i); i++; // . } } }

for. i , . , : i 10. i , , : 0 1 2 3 4 5 6 7 8 9

for . // for . using System; class Empty2 { public static void Main() { int i; i = 0; // . for(; i < 10; ) { Console.WriteLine(" " + i); i++; // . } } }

i for, . for.

116 I. C#

, , , , .

for,

(, ). , , C#- . for(;;) // . { // ... }

. (, ), , . , . (: break.)

C# , for ( - ), . , . . , 1 5. // . using System; class Empty3 { public static void Main() { int i; int sum = 0; // 1 5. for(i =1; i

5. 117

i. , : sum = sum + i; for

, for, . . , , 1 5. i for. // for. using System; class ForVar { public static void Main() { int sum = 0; int fact = 1; // 1 5. for(int i = 1; i

118 I. C#

, while . // . using System; class WhileDemo { public static void Main() { int num; int mag; num = 435679; mag = 0; Console.WriteLine(": " + num); while(num > 0) { mag++; num = num / 10; }; Console.WriteLine(": " + mag); } }

: : 435679 : 6

while . num. , mag , num 10. , num . num , , mag .

for, while, a , . ( ) . // 2. using System; class Power { public static void Main() { int e; int result; for(int i=0; i < 10; i++) { result = 1; e = i; while(e > 0) { result *= 2; e--; } Console.WriteLine("2 " + i + " " + result);

5. 119

} } }

: 2 0 1 2 1 2 2 2 3 2 3 4 2 4 16 2 5 32 2 6 64 2 7 128 2 8 256 2 9 512

, while , . , , for, while .

do-while

C# do-while. for while,

, do-while . , do-while . : do { ; } while();

, , do-while, while. do-while , , .

do-while , . // . using System; class DoWhileDemo { public static void Main() { int num; int nextdigit; num = 198; Console.WriteLine(": " + num); Console.Write(" : "); do { nextdigit = num % 10; Console.Write(nextdigit);

120 I. C#

num = num / 10; } while(num > 0); Console.WriteLine(); } }

: : 198 : 891

. 10. . num. , . , num .

foreach

foreach .

. C# , . foreach 7, .

break

break ,

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// break . using System; class BreakDemo { public static void Main() { // break . for(int i=-10; i 0) break; // i > 0. Console.Write(i + " "); } Console.WriteLine("!"); } }

: -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 !

5. 121

, , for i 10 10, break , i .

break C#-, . , , do-while-, : // break // do-while. using System; class BreakDemo2 { public static void Main() { int i; i = -10; do { if(i > 0) break; Console.Write(i + " "); i++; } while(i

122 I. C#

// break . using System; class BreakNested { public static void Main() { for(int i=0; i

5. 123

class ContDemo { public static void Main() { // 0 100. for(int i = 0; i

124 I. C#

goto case- default- switch. , , case- default- . , , goto. goto switch. , - goto switch. , goto switch. // goto switch. using System; class SwitchGoto { public static void Main() { for(int i=1; i < 5; i++) { switch(i) { case 1: Console.WriteLine(" case 1"); goto case 3; case 2: Console.WriteLine(" case 2"); goto case 1; case 3: Console.WriteLine(" case 3"); goto default; default: Console.WriteLine(" default"); break; } Console.WriteLine(); } // goto case 1; // ! // switch. } }

: case 1 case 3 default case 2 case 1 case 3 default case 3 default default

, goto case default switch. , case- break. goto case- case-,

5. 125

(break) . , goto switch-. // goto case 1; // !... . goto switch , , goto . : // goto. using System; class Use_goto { public static void Main() { int i=0, j=0, k=0; for(i=0; i < 10; i++) { for(j=0; j < 10; j++) { for(k=0; k < 10; k++) { Console.WriteLine("i, j, k: " + i + " " + j + " " + k); if(k == 3) goto stop; } } } stop: Console.WriteLine(", ! i, j, k: " + i + ", " + j + ", " + k); } }

: i, j, k: 0 0 0 i, j, k; 0 0 1 i, j, k: 0 0 2 i, j, k: 0 0 3 , ! i, j, k: 0, 0, 3

, goto, if break. goto . , , , , goto .

6. , 127

. C#, . , C#.

- C#. , . . , , C#, .

C#- , . , , . , , .

, . , . , , . C# . . , (), , . : . , , .

. , , , .

, , , ,

. , , .

, , . , -, , , , , , , . , . .

class. , , : class _ { // . 1; 2; //... N; // . _ 1() { // }

128 I. C#

_ 2() { // } _ N() { // } }

, . (, public), , . 2, . , . , , , , (private). ( ) . public-, , , , . 8.

( ), , . , , , ( ) , . , . , , .

, , Main(). , . , Main() . , .

,

(, , .). ( Building) ( , ).

Building. : floors, area occupants. , Building . . ( .) class Building { public int floors; // public int area; // public int occupants; // }

, Building, . : _;

6. , 129

, , _ . , , , . Building public, , , , Building.

class . Building. Building. , class ; . , Building.

Building, , , : Building house = new Building(); // // Building.

house Building, .. . .

, , . , Building floors, area occupants. (.). . : .

, , . , floors 2, . house.floors = 2;

, .

, Building. // , Building. using System; class Building { public int floors; // public int area; // public int occupants; // } // Building. class BuildingDemo { public static void Main() { Building house = new Building(); // // Building. int areaPP; // , . // house. house.occupants = 4; house.area = 2500; house.floors = 2;

130 I. C#

// , . areaPP = house.area / house.occupants; Console.WriteLine( " :\n " + house.floors + " \n " + house.occupants + " \n " + house.area + " , \n " + areaPP + " "); } }

: Building BuildingDemo. BuildingDemo Main() Building house, house, . , Building BuildingDemo . , . , BuildingDemo Building, , .. public-. public, Building, BuildingDemo .

UseBuilding.cs, UseBuilding.exe. Building BuildingDemo . : : 2 4 2500 , 625

Building BuildingDemo . Building.cs BuildingDemo.cs, . .

: csc Building.cs BuildingDemo.cs

Visual Studio IDE, .

, : , . , . , , . , Building floors, area occupants, () . . // Building. using System;

6. , 131

class Building { public int floors; // public int area; // public int occupants; // } // Building. class BuildingDemo { public static void Main() { Building house = new Building(); Building office = new Building(); int areaPP; // , . // house. house.occupants = 4; house.area = 2500; house.floors = 2; // office. office.occupants = 25; office.area = 4200; office.floors = 3; // , . areaPP = house.area / house.occupants; Console.WriteLine(" :\n " + house.floors + " \n " + house.occupants + " \n " + house.area + " , \n " + areaPP + " "); Console.WriteLine(); // , // . areaPP = office.area / office.occupants; Console.WriteLine(" :\n " + office.floors + " \n " + office.occupants + " \n " + office.area + " , \n " + areaPP + " "); } }

: : 2 4 2500 , 625 : 3 25 4200 , 168

132 I. C#

, ( house) ( office). . 6.1.

. 6.1.

Building. Building house = new Building(); . -,

house Building. , . -, house . new. , house Building.

new (.. ) . ( ) , new. , C# .

, , .

Building house; // . house = new Building(); // // Building.

house

Building. house , , . ( ) house null, , . Building, house. house .

, , , .

floorsarea

occupants

22500

4

house

floorsarea

occupants

34200

25

office

6. , 133

, . . , int x; x = 10; x 10, x int, .. . Building house = new Building(); house , .

,

(, int). ( ) , . ( ) . ( ) , , , . , :

Building house1 = new Building(); Building house2 = house1;

, house1 house2 , . , house1 house2, . house1 house2 house2 , house1, , house1, house2. , house1.area = 2600; , Console.WriteLine(house1.area); Console.WriteLine(house2.area); 2600.

, house1 house2, , . , house2 , . Building house1 = new Building(); Building house2 = house1; Building house3 = new Building(); Building house2 = house3; // house2 // house3 // . house2 , house3. , house1, .

134 I. C#

,

. Building . ( ) , . (), , , . .

. C#- . , . . , Main() , . , C#.

. , getval, getval(). .

: _ (_) { // }

, , . , , , , , (private) , . public-, , , .

_ , . , , . , void. , , . , , . _ ( ), . , , . , _ .

Building , , , ,

, . , , Main() , , .

, . , , Building, area occupants, Building. , Building

6. , 135

. , , , , . , . , Building , , , - , , . Building , . , Building areaPerPerson(), , . // Building. using System; class Building { public int floors; // public int area; // public int occupants; // // , // . public void areaPerPerson() { Console.WriteLine(" " + area / occupants + " "); } } // areaPerPerson(). class BuildingDemo { public static void Main() { Building house = new Building(); Building office = new Building(); // house. house.occupants = 4; house.area = 2500; house.floors = 2; // office. office.occupants = 25; office.area = 4200; office.floors = 3; Console.WriteLine(" :\n " + house.floors + " \n " + house.occupants + " \n " + house.area + " , "); house.areaPerPerson(); Console.WriteLine(); Console.WriteLine(" :\n " +

136 I. C#

office.floors + " \n " + office.occupants + " \n " + office.area + " , "); office.areaPerPerson(); } }

, : : 2 4 2500 , 625 : 3 25 4200 , 168

,

areaPerPerson(). : public void areaPerPerson() {

areaPerPerson(), . public, . areaPerPerson() void, .. . , .

. areaPerPerson() : Console.WriteLine(" " + area / occupants + " ");

, , area occupants. Building area occupants, areaPerPerson() , , , .

areaPerPerson() , .. .

Main(): house.areaPerPerson();

areaPerPerson() house. , , . , , , .

house.areaPerPerson() , , , house. office.areaPerPerson() , , ,

6. , 137

office. , , areaPerPerson(), , , , .

. area occupants areaPerPerson() , .. , . : , , , . , . , , , . , . , area occupants areaPerPerson() , , areaPerPerson().

. , ( areaPerPerson()), return. return: void- ( ), . , .

void- return: return;

, . , , : public void myMeth() { int i; for(i=0; i

138 I. C#

, : void- : return.

void- ,

. , . 3, Math.Sqrt() .

, , -. ( Math.Sqrt()) , , , , . , , , C#-.

, return: return ;

, .

areaPerPerson(). , , areaPerPerson() , . areaPerPerson(), , , ( ). // areaPerPerson(). using System; class Building { public int floors; // public int area; // public int occupants; // // , // . public int areaPerPerson() { return area / occupants; } } // areaPerPerson(). class BuildingDemo { public static void Main() { Building house = new Building(); Building office = new Building(); int areaPP; // , // . // house. house.occupants = 4; house.area = 2500; house.floors = 2;

6. , 139

// office. office.occupants = 25; office.area = 4200; office.floors = 3; // house , // . areaPP = house.areaPerPerson(); Console.WriteLine(" :\n " + house.floors + " \n " + house.occupants + " \n " + house.area + " , \n " + areaPP + " "); Console.WriteLine(); // office, // . areaPP = office.areaPerPerson(); Console.WriteLine(" :\n " + office.floors + " \n " + office.occupants + " \n " + office.area + " , \n " + areaPP + " "); } }

. areaPerPerson():

. , , areaPerPerson(). , areaPP = house.areaPerPerson(); , house, areaPP.

, areaPerPerson() , int. , . , , , , , , . , , double, double.

, . , areaPP. areaPerPerson() WriteLine(); Console.WriteLine(" :\n " + house.floors + " \n " +

140 I. C#

house.occupants + " \n " + house.area + " , \n " + house.areaPerPerson() + " ");

WriteLine() house.areaPerPerson(), WriteLine(). , house.areaPerPerson() , Building, . , . if(b1.areaPerPerson() > b2.areaPerPerson()) Console.WriteLine( " b1 .");

. , , , . , , . , . , . , , , .

. ChkNum isPrime, true, , false . , isPrime bool. // . using System; class ChkNum { // true, x - . public bool isPrime(int x) { for(int i=2; i < x/2 + 1; i++) if((x %i) == 0) return false; return true; } } class ParmDemo { public static void Main() { ChkNum ob = new ChkNum(); for(int i=1; i < 10; i++) if(ob.isPrime(i)) Console.WriteLine(i + " ."); else Console.WriteLine(i + " ."); } }

:

6. , 141

1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9 .

isPrime , . . -, , isPrime. . isPrime 1. x 1. 2, , 2 .. , , isPrime, , x.

. , . , , ChkNum, lcd(), (least common denominator) . // , . using System; class ChkNum { // true, x - . public bool isPrime(int x) { for(int i=2; i < x/2 + 1; i++) if((x %i) == 0) return false; return true; } // . public int lcd(int a, int b) { int max; if(isPrime(a) | isPrime(b)) return 1; max = a < b ? a : b; for(int i=2; i < max/2 + 1; i++) if(((a%i) == 0) & ((b%i) == 0)) return i; return 1; } } class ParmDemo { public static void Main() { ChkNum ob = new ChkNum(); int a, b; for(int i=1; i < 10; i++)

142 I. C#

if(ob.isPrime (i)) Console.WriteLine(i + " ."); else Console.WriteLine(i + " ."); a = 7; b = 8; Console.WriteLine(" " + a + " " + b + " " + ob.lcd(a, b)); a = 100; b = 8; Console.WriteLine(" " + a + " " + b + " " + ob.lcd(a, b)); a = 100; b = 75; Console.WriteLine(" " +

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