Chapter16:StringEscapeSequences

Section16.1:Escapingspecialsymbolsinstringliterals

Backslash

//Thefilenamewillbec:\myfile.txtinbothcases

stringfilename=”c:\\myfile.txt”;

stringfilename=@”c:\myfile.txt”;

Thesecondexampleusesaverbatimstringliteral,whichdoesn’ttreatthebackslashasanescapecharacter.

Quotes

stringtext=”\”HelloWorld!\”,saidthequickbrownfox.”;

stringverbatimText=@”””HelloWorld!””,saidthequickbrownfox.”;

Bothvariableswillcontainthesame text.

“Hello World!”, said the quickbrown fox.

Newlines

Verbatim string literals can contain newlines:

stringtext=”Hello\r\nWorld!”;

stringverbatimText=@”Hello

World!”;

Bothvariableswillcontainthesame text.

Section16.2:Unicodecharacterescapesequences

stringsqrt=”\\u221A”; //√

stringemoji=”\\U0001F601″;//?

stringtext=”\\u0022HelloWorld\\u0022″;//”HelloWorld”

stringvariableWidth=”\\x22HelloWorld\\x22″;//”HelloWorld”

Section16.3:Escapingspecialsymbolsincharacterliterals

Apostrophes

charapostrophe=’\’‘;

Backslash

charoneBackslash=’\\‘;

Section16.4:Usingescapesequencesinidentifiers

Escapesequencesarenotrestrictedtostringandcharliterals.

Supposeyouneedtooverrideathird-partymethod:

protectedabstractIEnumerable<Texte>ObtenirŒuvres();

andsupposethecharacterŒisnotavailableinthecharacterencodingyouuseforyourC#sourcefiles.Youare lucky,itispermittedtouseescapesofthetype\u####or\U########inidentifiersinthecode.Soitislegalto write:

protectedoverrideIEnumerable<Texte>Obtenir\u0152uvres()

{

//…

}

andthe C# compiler will knowŒand \u0152are the same character.

(However,itmightbeagoodideatoswitchtoUTF-8orasimilarencodingthatcanhandleallcharacters.)

Section16.5:Unrecognizedescapesequencesproduce compile-time errors

Thefollowing exampleswill not compile:

strings=”\c“;

charc=’\c‘;

Instead,theywillproducetheerrorUnrecognizedescapesequenceatcompiletime.