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The unchecked Keyword

Now, assuming you have enabled this projectwide setting, what are you to do if you have a block of

code where data loss 

is acceptable? Given that the /checked flag will evaluate all arithmetic logic, C#

provides the unchecked keyword to disable the throwing of an overflow exception on a case-by-case

basis. This keyword’s use is identical to that of the checked keyword in that you can specify a single

statement or a block of statements, for example:

// Assuming /checked is enabled,

// this block will not trigger

// a runtime exception.

unchecked

{

byte sum = (byte)(b1 + b2);

Console.WriteLine("sum = { 0} ", sum);

}

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So, to summarize the C# checked and unchecked keywords, remember that the default behavior

of the .NET runtime is to ignore arithmetic overflow. When you want to selectively handle discrete

statements, make use of the checked keyword. If you wish to trap overflow errors throughout your

application, enable the /checked flag. Finally, the unchecked keyword may be used if you have a

block of code where overflow is acceptable (and thus should not trigger a runtime exception).