C# Language Reference Owners: Anders Hejlsberg and Scott Wiltamuth File: C# Language Reference.doc Last saved: 6/12/2000 Last printed: 6/26/2000 Version 0.17b Copyright Microsoft Corporation 1999-2000 All Rights Reserved Notice This documentation is an early release of the final documentation, which may be changed substantially prior to final commercial release, and is information of Microsoft Corporation This document is provided for informational purposes only and Microsoft makes no warranties, either express or implied, in this document Information in this document is subject to change without notice The entire risk of the use or the results of the use of this document remains with the user Complying with all applicable copyright laws is the responsibility of the user Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property Unpublished work © 1999-2000 Microsoft Corporation All rights reserved Microsoft, Windows, Visual Basic, and Visual C++ are either registered trademarks or trademarks of Microsoft Corporation in the U.S.A and/or other countries Other product and company names mentioned herein may be the trademarks of their respective owners Copyright Microsoft Corporation 1999-2000 All Rights Reserved Table of Contents Table of Contents Introduction 1.1 Hello, world 1.2 Automatic memory management 1.3 Types 1.4 Predefined types 1.5 Array types 1.6 Type system unification .9 1.7 Statements 10 1.7.1 Statement lists and blocks 10 1.7.2 Labeled statements and goto statements 10 1.7.3 Local declarations of constants and variables .11 1.7.4 Expression statements 11 1.7.5 The if statement 11 1.7.6 The switch statement 12 1.7.7 The while statement 12 1.7.8 The statement .13 1.7.9 The for statement 13 1.7.10 The foreach statement 13 1.7.11 The break statement and the continue statement .14 1.7.12 The return statement .14 1.7.13 The throw statement .14 1.7.14 The try statement 14 1.7.15 The checked and unchecked statements 14 1.7.16 The lock statement 14 1.8 Classes .14 1.9 Structs 15 1.10 Interfaces 15 1.11 Delegates 17 1.12 Enums .18 1.13 Namespaces 18 1.14 Properties 19 1.15 Indexers 20 1.16 Events 21 1.17 Versioning .22 1.18 Attributes 24 Lexical structure 27 2.1 Phases of translation 27 2.2 Grammar notation 27 2.3 Pre-processing 28 2.3.1 Pre-processing declarations 28 2.3.2 #if, #elif, #else, #endif 29 2.3.3 Pre-processing control lines 30 2.3.4 #line 31 2.3.5 Pre-processing identifiers 31 2.3.6 Pre-processing expressions 31 2.3.7 Interaction with white space .32 2.4 Lexical analysis 33 2.4.1 Input 33 Copyright Microsoft Corporation 1999-2000 All Rights Reserved iii C# LANGUAGE REFERENCE 2.4.2 Input characters 33 2.4.3 Line terminators 33 2.4.4 Comments 33 2.4.5 White space 33 2.4.6 Tokens 33 2.5 Processing of Unicode character escape sequences 34 2.5.1 Identifiers 34 2.5.2 Keywords 36 2.5.3 Literals .36 2.5.3.1 Boolean literals .36 2.5.3.2 Integer literals .36 2.5.3.3 Real literals 37 2.5.3.4 Character literals 38 2.5.3.5 String literals .39 2.5.3.6 The null literal .40 2.5.4 Operators and punctuators 40 Basic concepts 41 3.1 Declarations 41 3.2 Members 43 3.2.1 Namespace members 43 3.2.2 Struct members 43 3.2.3 Enumeration members 44 3.2.4 Class members 44 3.2.5 Interface members .44 3.2.6 Array members 44 3.2.7 Delegate members .44 3.3 Member access 44 3.3.1 Declared accessibility 44 3.3.2 Accessibility domains 45 3.3.3 Protected access 47 3.3.4 Accessibility constraints .48 3.4 Signatures and overloading .49 3.5 Scopes 50 3.5.1 Name hiding 52 3.5.1.1 Hiding through nesting 52 3.5.1.2 Hiding through inheritance 53 3.6 Namespace and type names 54 3.6.1 Fully qualified names 55 Types 57 4.1 Value types .57 4.1.1 Default constructors 58 4.1.2 Struct types .59 4.1.3 Simple types .59 4.1.4 Integral types 60 4.1.5 Floating point types .61 4.1.6 The decimal type 62 4.1.7 The bool type 63 4.1.8 Enumeration types .63 4.2 Reference types .63 iv Copyright Microsoft Corporation 1999-2000 All Rights Reserved Table of Contents 4.2.1 Class types 64 4.2.2 The object type 64 4.2.3 The string type 64 4.2.4 Interface types 64 4.2.5 Array types .64 4.2.6 Delegate types 64 4.3 Boxing and unboxing 65 4.3.1 Boxing conversions .65 4.3.2 Unboxing conversions 66 Variables 67 5.1 Variable categories 67 5.1.1 Static variables 67 5.1.2 Instance variables 67 5.1.2.1 Instance variables in classes 67 5.1.2.2 Instance variables in structs 68 5.1.3 Array elements 68 5.1.4 Value parameters 68 5.1.5 Reference parameters 68 5.1.6 Output parameters .68 5.1.7 Local variables 69 5.2 Default values 69 5.3 Definite assignment 69 5.3.1 Initially assigned variables 72 5.3.2 Initially unassigned variables .72 5.4 Variable references 72 Conversions 73 6.1 Implicit conversions 73 6.1.1 Identity conversion 73 6.1.2 Implicit numeric conversions 73 6.1.3 Implicit enumeration conversions 74 6.1.4 Implicit reference conversions 74 6.1.5 Boxing conversions .74 6.1.6 Implicit constant expression conversions .74 6.1.7 User-defined implicit conversions .75 6.2 Explicit conversions 75 6.2.1 Explicit numeric conversions 75 6.2.2 Explicit enumeration conversions 76 6.2.3 Explicit reference conversions 76 6.2.4 Unboxing conversions 77 6.2.5 User-defined explicit conversions 77 6.3 Standard conversions 77 6.3.1 Standard implicit conversions .77 6.3.2 Standard explicit conversions .78 6.4 User-defined conversions 78 6.4.1 Permitted user-defined conversions .78 6.4.2 Evaluation of user-defined conversions 78 6.4.3 User-defined implicit conversions .79 6.4.4 User-defined explicit conversions 80 Expressions 81 Copyright Microsoft Corporation 1999-2000 All Rights Reserved v Chapter 21 References 21 References Unicode Consortium The Unicode Standard, Version 3.0 Addison-Wesley, Reading, Massachusetts, 2000, ISBN 0-201-616335-5 IEEEE IEEE Standard for Binary Floating-Point Arithmetic ANSI/IEEE Standard 754-1985 Available from http://www.ieee.org ISO/IEC C++ ANSI/ISO/IEC 14882:1998 Copyright Microsoft Corporation 1999-2000 All Rights Reserved 265 ... 44 3.3.1 Declared accessibility 44 3.3.2 Accessibility domains 45 3.3.3 Protected access 47 3.3.4 Accessibility constraints ... permission of Microsoft Corporation Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document Except as expressly... under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording,