C# AND F#

C# and F#Programming Language

C SHARP• It was developed by Microsoft within its .NET

initiative and later approved as a standard by Ecma (ECMA-334) and ISO (ISO/IEC 23270).

• C# is one of the programming languages designed for the Common Language Infrastructure.

• "C sharp" was inspired by musical notation where a sharp indicates that the written note should be made a semitone higher in pitch.

• C#'s principal designer and lead architect at Microsoft is Anders Hejlsberg, who was previously involved with the design of Turbo Pascal, Embarcadero Delphi.

Design Goals of C#• C# language is intended to be a simple, modern,

general-purpose, object-oriented programming language.

• The language, and implementations thereof, should provide support for software engineering principles such as strong type checking, array bounds checking, detection of attempts to use uninitialized variables, and automatic garbage collection.

• The language is intended for use in developing software components suitable for deployment in distributed environments.

• Source code portability is very important, as is programmer portability, especially for those programmers already familiar with C and C++.

Design Goals of C#

• Support for internationalization is very important.• C# is intended to be suitable for writing

applications for both hosted and embedded systems, ranging from the very large that use sophisticated operating systems, down to the very small having dedicated functions.

• Although C# applications are intended to be economical with regard to memory and processing power requirements, the language was not intended to compete directly on performance and size with C or assembly language.

Versions of C#Version

Language specificationDate .NET Framewor

kVisual Studio

ECMA ISO/IEC Microsoft

C# 1.0

December 2002

April 2003

January 2002

January 2002 .NET Framework 1.0

Visual Studio .NET 2002

C# 1.2 October 2003

April 2003 .NET Framework 1.1

Visual Studio .NET 2003

C# 2.0 June 2006 September 2006

September 2005

November 2005

.NET Framework 2.0

Visual Studio 2005

C# 3.0

None

August 2007

November 2007

.NET Framework 2.0 (Except LINQ/Query Extensions).NET Framework 3.0 (Except LINQ/Query Extensions).NET Framework 3.5

Visual Studio 2008

C# 4.0 April 2010 April 2010 .NET Framework 4

Visual Studio 2010

Distinguishing Features of C#

• It has no global variables or functions. All methods and members must be declared within classes. Static members of public classes can substitute for global variables and functions.

• Local variables cannot shadow variables of the enclosing block, unlike C and C++. Variable shadowing is often considered confusing by C++ texts.

• C# supports a strict Boolean data type.• In C#, memory address pointers can only be used

within blocks specifically marked as unsafe, and programs with unsafe code need appropriate permissions to run.

• Managed memory cannot be explicitly freed.

Distinguishing Features of C#• Multiple inheritance is not supported, although a

class can implement any number of interfaces.• C# is more type safe than C++. • C# currently (as of version 4.0) has 77 reserved

words.

Categories of data types• Value types

Value types are plain aggregations of data. Instances of value types do not have referential identity nor a referential comparison semantics - equality and inequality comparisons for value types compare the actual data values within the instances, unless the corresponding operators are overloaded.

Examples of value types are all primitive types, such as int (a signed 32-bit integer), float (a 32-bit IEEE floating-point number), char (a 16-bit Unicode code unit), and System.DateTime (identifies a specific point in time with nanosecond precision).

Categories of data types• Reference types

reference types have the notion of referential identity - each instance of a reference type is inherently distinct from every other instance, even if the data within both instances is the same.

Examples of reference types are object (the ultimate base class for all other C# classes), System.String (a string of Unicode characters), and System.Array (a base class for all C# arrays).

Code comments• C# utilizes a double forward slash (//) to indicate the rest of the line

is a comment. This is inherited from C++.public class Foo{ // a comment public static void Bar(int firstParam) {} // also a comment}Multi-line comments can be indicated by a starting forward slash/asterisk (/*) and ending asterisk/forward slash (*/). This is inherited from standard C.public class Foo{ /* A Multi-Line comment */ public static void Bar(int firstParam) {}}

Preprocessor• C# features "preprocessor directives" (though it does not have an actual

preprocessor) based on the C preprocessor that allow programmers to define symbols but not macros. Conditionals such as #if, #endif, and #else are also provided. Directives such as #region give hints to editors for code folding.

public class Foo{ #region Procedures public void IntBar(int firstParam) {} public void StrBar(string firstParam) {} public void BoolBar(bool firstParam) {} #endregion #region Constructors public Foo() {} public Foo(int firstParam) {} #endregion}

"Hello world" example

using System; class Program{ static void Main() { Console.WriteLine("Hello world!"); }}

using System;The using statement allows the programmer to

state all candidate prefixes to use during compilation instead of always using full type names.

class ProgramAbove is a class definition. Everything between the

following pair of braces describes Program.static void Main()This declares the class member method where the

program begins execution. The void keyword declares that Main has no return value.

Console.WriteLine("Hello world!");The program calls the Console method WriteLine,

which displays on the console a line with the argument, the string "Hello world!".

Comparison of C Sharp and Java

• Both languages are considered "curly brace" languages in the C/C++ family. Overall the syntaxes of the languages are very similar.

• The syntax at the statement and expression level is almost identical with obvious inspiration from the C/C++ tradition.

• Java is explicit about extending classes and implementing interfaces, while C# infers this from the kind of types a new class/interface derives from.

• C# supports more features than Java which to some extent is also evident in the syntax which specifies more keywords and more grammar rules than Java.

Simple/primitive typesType Name BCL Equivalent Value Range Size Default Value

sbyte System.SByte integer −128 through +127 8-bit (1-byte) 0

short System.Int16 integer−32,768 through +32,767

16-bit (2-byte) 0

int System.Int32 integer−2,147,483,648 through +2,147,483,647

32-bit (4-byte) 0

long System.Int64 integer

−9,223,372,036,854,775,808 through+9,223,372,036,854,775,807

64-bit (8-byte) 0

byte System.Byte unsigned integer 0 through 255 8-bit (1-byte) 0

ushort System.UInt16 unsigned integer 0 through 65,535 16-bit (2-byte) 0

uint System.UInt32 unsigned integer0 through 4,294,967,295

32-bit (4-byte) 0

ulong System.UInt64 unsigned integer0 through 18,446,744,073,709,551,615

64-bit (8-byte) 0

decimal System.Decimalsigned decimal number

−7.9228162514264337593543950335 through+7.9228162514264337593543950335

128-bit (16-byte) 0.0

float System.Single floating point number±1.401298E−45 through ±3.402823E+38

32-bit (4-byte) 0.0

double System.Double floating point number

±4.94065645841246E−324 through±1.79769313486232E+308

64-bit (8-byte) 0.0

bool System.Boolean Boolean true or false 8-bit (1-byte) false

char System.Charsingle Unicode character

'\u0000' through '\uFFFF' 16-bit (2-byte) '\u0000'

Advanced numeric types

Java C#

BigInteger bigNumber = new BigInteger("123456789012345678901234567890"); BigInteger answer = bigNumber.multiply(new BigInteger("42"));BigInteger square = bigNumber.multiply(bigNumber);BigInteger sum = bigNumber.add(bigNumber);

BigInteger bigNumber = BigInteger.Parse("123456789012345678901234567890"); var answer = bigNumber * 42;var square = bigNumber * bigNumber;var sum = bigNumber + bigNumber;

Lifted (nullable) types

Java C#Integer a = 42;Integer b = null; // This will generate a runtime NullPointerException,// because it attempts to unbox the null value.Integer c = a * b;

int? a = 42;int? b = null; // c will receive the null value// because * is lifted and one of the operands are nullint? c = a * b;

Special feature keywordskeyword feature, example usage

checked, uncheckedIn C#, checked statement blocks or expressions can enable run-time checking for arithmetic overflow.

get, set

C# implements properties as part of the language syntax with their optional corresponding get and set accessors, as an alternative for the accessor methods used in Java, which is not a language feature but a coding-pattern based on method name conventions.

goto

C# supports the goto keyword. This can occasionally be useful, for example for implementing finite state machines or for generated code, but the use of a more structured method of control flow is usually recommended (see criticism of the goto statement). Java does not support the goto statement (but goto is a reserved word). However, Java does support labeled break and continue statements, which in certain situations can be used when a goto statement might otherwise be used. switch(color){ case Color.Blue: Console.WriteLine("Color is blue"); break; case Color.DarkBlue: Console.WriteLine("Color is dark"); goto case Color.Blue; // ...}

lockIn C#, the lock keyword is a shorthand for synchronizing access to a block of code across threads (using a Monitor), wrapped in a try ... finally block.

Special feature keywords

out, refC# has support for output and reference parameters. These allow returning multiple output values from a method, or passing values by reference.

strictfp Java uses strictfp to guarantee the results of floating point operations remain the same across platforms.

switch

In C#, the switch statement also operates on strings and longs but only allows fallthrough for empty statements. Java's switch statement does not operate on strings nor long primitive type but falls through for all statements (excluding those with 'break').

throws

Java requires every method to declare the checked exceptions or superclasses of the checked exceptions that it can throw. Any method can also optionally declare the unchecked exception that it throws. C# has no such syntax. public int readItem() throws java.io.IOException{ // ...}

using

In C#, using causes the Dispose method (implemented via the IDisposable interface) of the object declared to be executed after the code block has run or when an exception is thrown within the code block. // Create a small file "test.txt", write a string,// ... and close it (even if an exception occurs)using (StreamWriter file = new StreamWriter("test.txt")){ file.Write("test");}

C Sharp Identifier• An identifier can:

start with a "_".contain both upper case and lower case Unicode letters.

Case is significant.

• An identifier cannot:start with a numeral.start with a symbol, unless it is a keyword (check Keywords).

have more than 511 chars.

C# keywords, reserved wordsabstract as base boolbreak by 2 byte casecatch char checkedclass

constcontinue

decimal default

delegate do double descending 2

explicit event extern else

enum false finally fixedfloat for foreach from 2

goto group 2if implicit

in intinterface

internal

into 2 is lock long

new nullnamespace

object

operator out overrideorderby 2

params privateprotected

public

readonly ref return switch

struct sbyte sealed short

sizeofstackalloc

static string

select 2 this throw true

try typeof uint ulong

unchecked unsafe ushort using

var 2 virtual volatile void

whilewhere 2

yield 1  

Integers

hexadecimal 0xF5, 0x[0..9, A..F, a..f]+

decimal 245, [0..9]+

Floating-point values

float23.5F, 23.5f; 1.72E3F, 1.72E3f, 1.72e3F, 1.72e3f

double 23.5, 23.5D, 23.5d; 1.72E3, 1.72E3D, ...

Dates

date not possible

Characters

char 'a', 'Z', '\u0231'

Strings

String"Hello, world"

"C:\\Windows\\", @"C:\Windows\"

C Sharp Literals

C Sharp LiteralsCharacters escapes in strings

Unicode character\u followed by the hexadecimal unicode code point

Tab \t

Backspace \b

Carriage return \r

Form feed \f

Backslash \\

Single quote \'

Double quote \"

Line feed \n

Variables• Variables are identifiers associated with values. They are

declared by writing the variable's type and name, and are optionally initialized in the same statement by assigning a value.

• Declareint MyInt; // Declaring an uninitialized variable called 'MyInt', of type 'int'• Initializeint MyInt; // Declaring an uninitialized variableMyInt = 35; // Initializing the variable• Declare & initializeint MyInt = 35; // Declaring and initializing the variable at the same time

OperatorsOperator category Operators

Arithmetic + - * / %Logical (boolean and bitwise)

& | ^ ! ~ && ||

String concatenation +Increment, decrement ++ --Shift << >>Relational == != < > <= >=Assignment = += -= *= /= %= &= |= ^= <<= >>=Member access .Indexing [ ]Cast ( )Conditional ?  :Delegate concatenation and removal

+ -

Object creation newType information as is sizeof typeofOverflow exception control checked uncheckedIndirection and Address * -> [] &

Conditional structures

• if statementThe if statement is entered when the given condition is

true. Single-line case statements do not require block braces although it is mostly preferred by convention.

Simple one-line statement:if (i == 3) ... ;

Multi-line with else-block (without any braces):if (i == 2) ...else ...

Conditional structures• switch statement

The switch construct serves as a filter for different values. switch (ch){ case 'A': ... break; case 'B': case 'C': ... break; default: ... break;}

Jump statements• The goto statement can be used in switch statements

to jump from one case to another or to fall through from one case to the next.

switch(n){ case 1: Console.WriteLine("Case 1"); break; case 2: Console.WriteLine("Case 2"); goto case 1; case 3: Console.WriteLine("Case 3"); case 4: // Compilation will fail here as cases cannot fall through in C#. Console.WriteLine("Case 4"); goto default; // This is the correct way to fall through to the next case. default: Console.WriteLine("Default");}

Iteration structures• while loopwhile (i == true){ ...}• do ... while loopdo{ ...}while (i == true);• for loop

The for loop consists of three parts: declaration, condition and increment. Any of them can be left out as they are optional.

for (int i = 0; i < 10; i++){ ...}

break statement• The break statement breaks out of the closest loop

or switch statement. Execution continues in the statement after the terminated statement, if any.

int e = 10;for (int i=0; i < e; i++){ while (true) { break; } // Will break to this point.}

continue statement• The continue statement discontinues the current

iteration of the current control statement and begins the next iteration.

int ch;while ((ch = GetChar()) >= 0){ if (ch == ' ') continue; // Skips the rest of the while-loop // Rest of the while-loop ...}

Modifiers• Modifiers are keywords used to modify declarations of types and

type members. Most notably there is a sub-group containing the access modifiers.abstract - Specifies that a class only serves as a base class. It must be

implemented in an inheriting class.const - Specifies that a variable is a constant value that has to be initialized

when it gets declared.event - Declare an event.extern - Specify that a method signature without a body uses a DLL-import.override - Specify that a method or property declaration is an override of a

virtual member or an implementation of a member of an abstract class.readonly - Declare a field that can only be assigned values as part of the

declaration or in a constructor in the same class.sealed - Specifies that a class cannot be inherited.static - Specifies that a member belongs to the class and not to a specific

instance. (see section static)unsafe - Specifies an unsafe context, which allows the use of pointers.virtual - Specifies that a method or property declaration can be overridden

by a derived class.volatile - Specifies a field which may be modified by an external process and

prevents an optimizing compiler from modifying the use of the field.

F SHARP• F# is a multi-paradigm programming language,

targeting the .NET Framework, that encompasses functional programming as well as imperative and object-oriented programming disciplines.

• It is a variant of ML and is largely compatible with the OCaml implementation.

• F# was initially developed by Don Syme at Microsoft Research but is now being developed at Microsoft Developer Division and is being distributed as a fully supported language in the .NET Framework and Visual Studio as part of Visual Studio 2010.

• F# is a strongly typed language that uses type inference.

F SHARP• F# uses pattern matching to resolve names into

values. It is also used when accessing discriminated unions.

• F# comes with a Microsoft Visual Studio language service that integrates it with the IDE.

• All functions in F# are instances of the function type, and are immutable as well.

• The F# extended type system is implemented as generic .NET types.

Examples• A few small samples follow:

(* This is a comment *)(* Sample hello world program *)

printfn "Hello World!"

Operatorsindentation

block (grouping statements, especially when statements are not expressions)

nothing neededbreaking lines (useful when end-of-line and/or indentation has a special meaning)

(* ... *) commenting (nestable)

// commenting (until end of line)

< > <= >= comparison

min / max comparison (min / max (binary or more))

comparecomparison (returns 3 values (i.e. inferior, equal or superior))

(** ... *) documentation comment (non nestable)

/// documentation comment (until end of line)

= <> equality / inequality (deep)

== != equality / inequality (shallow)

System.GC.Collect() force garbage collection

( ... ) grouping expressions

Operatorsbegin ... end grouping expressions

__LINE__ __SOURCE_FILE__information about the current line and file

case-sensitivetokens (case-sensitivity (keywords, variable identifiers...))

[_a-zA-Z][_a-zA-Z0-9']* tokens (variable identifier regexp)

CamelCase for methods, types and modules, underscore for functions

tokens (what is the standard way for scrunching together multiple words)

<-variable assignment or declaration (assignment)

let v = e invariable assignment or declaration (declaration)

let v = e(1)variable assignment or declaration (declaration)

Functions

(>) a

partial application (in the examples below, a normal call is "f(a,b)") (give the first argument to operator ">")

f apartial application (in the examples below, a normal call is "f(a,b)") (give the first argument)

fun a b -> ... anonymous function

f a b ... function call

f() function call (with no parameter)

<<  function composition

>>  function composition

let f para1 para2 = ... function definition

no syntax needed(2)function return value (function body is the result)

Control Flow try a with exn -> ... exception (catching)

finallyexception (cleanup: code executed before leaving)

raise exception (throwing)

if c then ... if_then

if c then b1 else b2 if_then_else

for i = 10 downto 1 do ... done

loop (for each value in a numeric range, 1 decrement)

for i in 10 .. -1 .. 1 do ... done

loop (for each value in a numeric range, 1 decrement)

for i = 1 to 10 do ... doneloop (for each value in a numeric range, 1 increment (see also the entries about ranges))

Control Flow

for i in 1 .. 10 do ... doneloop (for each value in a numeric range, 1 increment (see also the entries about ranges))

for i in 1 .. 2 .. 10 do ... done

loop (for each value in a numeric range, free increment)

while c do ... done loop (while condition do something)

while c do ...

loop (while condition do something)

match val with | v1 -> ... | v2 | v3 -> ... | _ -> ...

multiple selection (switch)

; sequence

end-of-line sequence

Types

:annotation (or variable declaration)

t ecast (computed conversion (calls an internal or a user-defined function))

e :?> tcast (downcast (need runtime checking))

downcast e(3)cast (downcast (need runtime checking))

e : t cast (upcast)

upcast e cast (upcast)

type n = t declaration

constness is the default

mutability, constness (type of a constant value)

T refmutability, constness (type of a mutable value)

Strings s.[n] accessing n-th character

chr ascii to character

'z' character "z"

ord character to ascii

char character type name

ToString convert something to a string (see also string interpolation)

s.[n..m] extract a substring

sub extract a substring

IndexOf locate a substring

LastIndexOf locate a substring (starting at the end)

all strings allow multi-line strings

multi-line

BinaryFormatter.Serialize serialize (marshalling)

Strings

print_any simple print (on any objects)

WriteLine simple print (on any objects)

print_string simple print (on strings)

printf simple print (printf-like)

sprintf sprintf-like

Format sprintf-like

+ string concatenation

^ string concatenation

= <> string equality & inequality

Stringslength string size

Length string size

"..."strings (with no interpolation of variables)

stringBinaryFormatter.Deserialize type name

unserialize (un-marshalling)

uppercase / lowercase upper / lower case character

ToUpper / ToLower upper / lower case character

uppercase/lowercaseuppercase / lowercase / capitalized string

ToUpper / ToLoweruppercase / lowercase / capitalized string

Booleans

false false value

not logical not

|| / &&logical or / and (short circuit)

true true value

bool type name

Mathematics + / - / * / / addition / subtraction / multiplication / division

&&& / ||| / ^^^ bitwise operators (and / or / xor)

land / lor / lxor bitwise operators (and / or / xor)

~~~ bitwise operators (bitwise inversion)

lnot bitwise operators (bitwise inversion)

<<< / >>>bitwise operators (left shift / right shift / unsigned right shift)

lsl / lsr or asrbitwise operators (left shift / right shift / unsigned right shift)

** exponentiation (power)

log10 logarithm (base 10)

log logarithm (base e)

% modulo (modulo of -3 / 2 is -1)

mod modulo (modulo of -3 / 2 is -1)

- negation

1000., 1E3 numbers syntax (floating point)

0b1, 0o7, 0xfnumbers syntax (integers in base 2, octal and hexadecimal)

1000 numbers syntax (integers)

Mathematics

let r = System.Random()r.Next()

random (random number)

sqrt / exp / abssquare root / e-exponential / absolute value

sin / cos / tan trigonometry (basic)

asin / acos / atan(7) trigonometry (inverse)

int / / floor / ceil truncate / round / floor / ceil

int_of_float / / floor / ceil truncate / round / floor / ceil

float, float32 type name (floating point)

int, int8, uint8, int16, uint16, int32, uint32, int64, uint64, bigint, bignum

type name (integers)

The End

Presented by:

Harry Kim BaloisBSCS 41A