Chapter81:Overflow

Section81.1:Integeroverflow

Thereisamaximumcapacityanintegercanstore.Andwhenyougooverthatlimit,itwillloopbacktothenegative side. For int, it is 2147483647

intx=int.MaxValue; //MaxValueis2147483647

x=unchecked(x+1); //makeoperationexplicitlyuncheckedsothattheexamplealso

workswhenthecheckforarithmeticoverflow/underflowisenabledintheprojectsettings Console.WriteLine(x);    //Willprint-2147483648 Console.WriteLine(int.MinValue);             //SameasMinvalue

ForanyintegersoutofthisrangeusenamespaceSystem.NumericswhichhasdatatypeBigInteger.Checkbelow linkformoreinformationhttps://msdn.microsoft.com/en-us/library/system.numerics.biginteger(v=vs.110).aspx

Section81.2:Overflowduringoperation

Overflowalsohappensduringtheoperation.Inthefollowingexample,xisanint,1isanintbydefault.Therefore addition is an intaddition. And the result will be an int.And it will overflow.

intx=int.MaxValue; //MaxValueis2147483647

longy=x+1; //Itwillbeoverflown

Console.WriteLine(y); //Willprint-2147483648

Console.WriteLine(int.MinValue); //SameasMinvalue

Youcanpreventthatbyusing1L.Now1willbealongandadditionwillbealongaddition

intx=int.MaxValue; //MaxValueis2147483647

longy=x+1L; //ItwillbeOK

Console.WriteLine(y); //Willprint2147483648

Section81.3:Orderingmatters

Thereisoverflowinthefollowingcode

intx=int.MaxValue;

Console.WriteLine(x+x+1L);                 //prints-1

Whereasinthefollowingcodethereisno overflow

intx=int.MaxValue;

Console.WriteLine(x+1L+x);                //prints4294967295

Thisisduetotheleft-to-rightorderingoftheoperations.Inthefirstcodefragmentx+xoverflowsandafterthatit becomesalong.Ontheotherhandx+1Lbecomeslongandafterthatxisaddedtothisvalue.