Csharp/C Sharp/Data Types/checked unchecked

Checked and Unchecked

<source lang="csharp">

using System; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       Console.WriteLine("Max value of byte is {0}.", byte.MaxValue);
       Console.WriteLine("Min value of byte is {0}.", byte.MinValue);
       byte b1 = 100;
       byte b2 = 250;
       try {
           checked {
               byte sum = (byte)(b1 + b2);
               byte b4, b5 = 100, b6 = 200;
               b4 = (byte)(b5 + b6);
               Console.WriteLine("sum = {0}", sum);
           }
       } catch (OverflowException e) {
           Console.WriteLine(e.Message);
       }
       unchecked {
           byte sum = (byte)(b1 + b2);
           Console.WriteLine("sum = {0}", sum);
       }
   }

}

      </source>

Checking for overflows.

<source lang="csharp">

using System; public class MainClass {

   public int CheckedAddition(short s1, short s2) {
       int z = 0;
       try {
           z = checked((short)(s1 + s2));
       } catch (OverflowException) {
           Console.WriteLine("Overflow Exception, Returning 0");
       }
       return z;
   }
   public int UncheckedAddition(short s1, short s2) {
       int z = ((short)(s1 + s2));
       return z;
   }
   public static void Main() {
       MainClass app = new MainClass();
       short s1 = 32767;
       short s2 = 32767;
       Console.WriteLine("Checked Addition is: {0}",app.CheckedAddition(s1, s2));
       Console.WriteLine("Unchecked Addition is: {0}",app.UncheckedAddition(s1, s2));
   }

}

</source>

Demonstates using checked keyword to detect an overflow

<source lang="csharp"> // Compile this program with the following command line: // C:>csc /checked OvrFlow2.cs

   using System;
   public class OvrFlow2
   {
       static public void Main ()
       {
           int large = 2147483647;
           int larger = large;
           unchecked
           {
               ++larger;
               larger *= 2;
           }
           Console.WriteLine ("large = " + large);
           Console.WriteLine ("larger = " + larger);
       }
   }
          
      </source>

Demonstates using checked keyword to detect an overflow 2

<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794

• /

// // OvrFlow1.cs -- Demonstates using checked keyword to detect an overflow. // // Compile this program with the following command line: // C:>csc OvrFlow1.cs // namespace nsOverflow {

   using System;
   
   public class OvrFlow1
   {
       static public void Main ()
       {
           int large = 2147483647;
           int larger = large;
           try
           {
               larger = checked (++larger);
           }
           catch (OverflowException e)
           {
               Console.WriteLine ("The operation caused an overflow");
               Console.WriteLine (e.Message);
           }
           Console.WriteLine ("large = " + large);
           Console.WriteLine ("larger = " + larger);
       }
   }

}

      </source>

Operators and Expressions:Checked and Unchecked Expressions

<source lang="csharp"> using System; public class CheckedandUncheckedExpressions {

   public static void Main()
   {
       unchecked
       {
           byte a = 55;
           byte b = 210;
           byte c = (byte) (a + b);
       }
   }

}

      </source>

OverflowCheck

<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       byte destinationVar;
       short sourceVar = 281;
       destinationVar = checked((byte)sourceVar);
       Console.WriteLine("sourceVar val: {0}", sourceVar);
       Console.WriteLine("destinationVar val: {0}", destinationVar);
   }

}

</source>

unchecked int overflow

<source lang="csharp"> using System;

class IntegerOverFlowConst {

   static void Main()
   {
       const ushort MAXUSHORT = 65535;
       const ushort ONE = 1;
  
       unchecked
       {
           ushort total = (short)MAXUSHORT + ONE;
       }
   }

}

</source>