unsigned int usage

[siavoshkc]

In Stroustrup book we read:

Using an unsigned instead of an int to gain one more bit to represent positive integers is
almost never a good idea. Attempts to ensure that some values are positive by declaring
variables unsigned will typically be defeated by the implicit conversion rules (§C.6.1, §C.6.2.1).

But here we see

Arrays are not self-describing because the number of elements of an array is not guaranteed to
be stored with the array. This implies that to traverse an array that does not contain a
terminator the way character strings do, we must somehow supply the number of elements.
For example:

void fp (char v[], unsigned int size)
{
    for (int i=0; i<size; i++) use(v[i] );
    const int N =7;
    char v2[N];
    for (int i=0; i<N; i++) use(v2[i] );
}

Why he used unsigned int for "size" parameter? BTW what is the type of indexer? It should be as large as a pointer I think as it can access whole memory.
If &vec[0] is the lowest address accessible and &vec[n] is the highest address accessible which is &vec[0] + (n*sizeof(typeof(vec[0]))) then if type is char, n should be able to hold the highest address - lowest address much like a pointer.

[Codeplug]

There was a flame war about it on CLC++ not too long ago - here's a choice posting (the entire thread is bit bloated):
http://groups.google.com/group/comp....9587534a34b221

gg

[GReaper]

unsigned int is used instead of an int because:
It can contain a bigger number ( Max_signed_int * 2 )
It hints the user that a non-negative value is expected

None is better than the other! Each has its own area of expertise. The programmer just chooses the best for his/her current project.

For instance:

int mult(int a, int b) { return a*b; } // For common numbers

unsigned int mult(unsigned int a, unsigned int b) { return a*b; } // For big physical numbers

[CornedBee]

That said, the example code by Stroustrup here is bad because it mixes signed and unsigned ints. You can use unsigneds or leave them be, whatever your preference is, but be very careful when mixing signeds and unsigneds, or very subtle bugs can occur. Also, the compiler warnings are annoying.

[siavoshkc]

Sipher, did you read the Bjarne quotes and Codeplug link?