C# byte addition overflow?

Question

I noticed that when Byte plus Byte, it will produce int, Is it possible to let byte a +byte b and produce 255 if it overflows?

Byte a=200;
Byte b=200
Byte output = (a+b); // now output equals 144, I want 255

Are you sure that that is a good idea? What's the requirement behind it? Just look: now output - a doesn't equal b anymore! — Bernhard Hiller
– Bernhard Hiller, Commented Sep 16, 2016 at 7:56
@BernhardHiller there are a lot of use cases where you want that behaviour ... e.g. calculations with colors ^^ — derHugo
– derHugo, Commented Sep 1, 2021 at 13:27

Pepernoot · Accepted Answer · 2016-09-16 07:12:05Z

6

How about this (untested)?

byte output = (byte)(Math.Min(a + b, Byte.MaxValue));

edited Sep 16, 2016 at 7:12

Pepernoot

3,6433 gold badges27 silver badges49 bronze badges

answered Sep 16, 2016 at 7:01

user94559

60.3k6 gold badges108 silver badges107 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Dmitrii Bychenko Over a year ago

Probably byte.MaxValue is a bit more readable than magic constant 255

Visual Vincent · Accepted Answer · 2016-09-16 07:03:45Z

1

This usually happens when a number overflows which is not in a checked statement.

If you want it to produce 255 then the most simple option I can think of would be to use a ternary operation:

byte output = (int)a + (int)b > byte.MaxValue ? byte.MaxValue : a + b;

The other option I can think of would be to create your own data type that handles this for you.

answered Sep 16, 2016 at 7:03

Visual Vincent

18.4k5 gold badges33 silver badges83 bronze badges

Comments

Dmitrii Bychenko · Accepted Answer · 2016-09-16 07:06:46Z

1

Since a + b is of type int you can easily check:

  Byte a = 200;
  Byte b = 200

  byte result = a + b > byte.MaxValue ? byte.MaxValue : (byte) (a + b);

edited Sep 16, 2016 at 7:06

answered Sep 16, 2016 at 7:05

Dmitrii Bychenko

188k20 gold badges178 silver badges231 bronze badges

Comments

eocron · Accepted Answer · 2016-09-16 07:07:56Z

0

This will throw OverflowException:

checked
{
    Byte a=200;
    Byte b=200
    Byte output = (a+b);
}

And this way you can catch and process it:

Byte output;
try
{
    checked
    {
        Byte a=200;
        Byte b=200
        output = (a+b);
    }
}
catch(OverflowException e)
{
    output = Byte.MaxValue;
}
Console.WriteLine(output);

But I suggest you to control your flow yourself. Catching exceptions is bad approach, but if you have complex calculation, it can be troublesome. Just use Math instead:

var output = (Byte)Math.Min((int)a+b, Byte.MaxValue);

edited Sep 16, 2016 at 7:07

answered Sep 16, 2016 at 7:01

eocron

7,5962 gold badges27 silver badges62 bronze badges

Collectives™ on Stack Overflow

C# byte addition overflow?

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related