Why is Count not an unsigned integer? [duplicate]

Answer 1

Let’s look at this from a practical angle.

For better or worse, signed ints are the normal sort of ints in use in .NET. It was also normal to use signed ints in C and C++. So, most variables are declared to be int rather than unsigned int unless there is a good reason otherwise.

Converting between an unsigned int and a signed int has issues and is not always safe.

On a 32 bit system it is not possible for a collection to have anywhere close to 2^^32 items in it, so a signed int is big enough in all cases.

On a 64 bit system, an unsigned int does not gain you much, in most cases a signed int is still big enough, otherwise you need to use a 64 bit int. (I expect that none of the standard collection will cope well with anywhere near 2^^31 items on a 64 system!)

Therefore given that using an unsigned int has no clear advantage, why would you use an unsigned int?

Answer 2

Mabye because the uint data type is not part of the CLS (common language specification) as not all .Net languages support it.

Here is very similar thread about arrays:

Why is Array.Length an int, and not an uint

Answer 3

1. It's not CLS compliant, largely to allow wider support from different languages.

2. A signed int offers ease in porting code from C or C++ that uses pointer arithmetic.

3. Count can be part of an expression where the overall value can be negative. In particular, count has a direct relationship to indices, where valid indices are always in the range [0, Count - 1], but negative results are used e.g. by some binary search methods (including those provided by the BCL) to reflect the position where a new item should be inserted to maintain order.

Answer 4

In vb.net, the normal looping construct (a "For/Next loop") will execute the loop with values up to and including the maximum value specified, unlike C which can easily loop with values below the upper limit. Thus, it is often necessary to specify a loop as e.g. "For I=0 To Array.Length-1"; if Array.Length were unsigned and and zero, that could cause an obvious problem. Even in C, one benefits from being able to say "for (i=Array.Length-1; i GE 0; --i)". Sometimes I think it would be useful to have a 31-bit integer type which would support widening casts to both signed and unsigned int, but I've never heard of a language supporting such.

Answer 5

Unsigned integer is not CLS-compliant (Common Language Specification)

For more info on CLS compliant code, see this link:

http://msdn.microsoft.com/en-us/library/bhc3fa7f.aspx