Chapter 81: Overflow

Section 81.1: Integer overflow

There is a maximum capacity an integer can store. And when you go over that limit, it will loop back to the negative side. For int, it is 2147483647

For any integers out of this range use namespace System.Numerics which has datatype BigInteger. Check below link for more information https://msdn.microsoft.com/en-us/library/system.numerics.biginteger(v=vs.110).aspx

Section 81.2: Overflow during operation

Overflow also happens during the operation. In the following example, x is an int, 1 is an int by default. Therefore addition is an int addition. And the result will be an int. And it will overflow.

You can prevent that by using 1L. Now 1 will be a long and addition will be a long addition

Section 81.3: Ordering matters

There is overflow in the following code

int x = int.MaxValue;

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

Whereas in the following code there is no overflow

int x = int.MaxValue;

Console.WriteLine(x + 1L + x); //prints 4294967295

This is due to the left-to-right ordering of the operations. In the first code fragment x + x overflows and after that it becomes a long. On the other hand x + 1L becomes long and after that x is added to this value.