Re: pointer argument trouble

From:

"Jim Langston" <tazmaster@rocketmail.com>

Newsgroups:

comp.lang.c++

Date:

Tue, 23 May 2006 13:54:46 -0700

Message-ID:

<yEKcg.184$LZ.178@fe05.lga>

"Victor Bazarov" <v.Abazarov@comAcast.net> wrote in message
news:e4vrqn$mpj$1@news.datemas.de...

Jim Langston wrote:

"voidtwerp" <voidtwerp@gmail.com> wrote in message
news:1148396593.949362.288260@i39g2000cwa.googlegroups.com...

Am I being really stupid here - I cant see what the problem is.

how can I be getting different values in coincount[i] and count?
(note that I dont think either is correct but I cannot be sure at
this stage).

// 3rd party dll header file
extern "C" {
APIDLL_EXPORT bool _cdecl ENGINE_GetCoinCount(uint CoinValue,ulong*
cnt);
}

// my .cpp file

void Help_ProductSale_CountCoins(uint coinvalue[],ulong coincount[])
{
ulong count;
for(int i=6;i--;)
{
ENGINE_GetCoinCount(coinvalue[i],&coincount[i]);

Warning: you passed coinvalue which was declared in Test_ProductSale
as: uint coinvalue[]={5,10,20,50,100,200};
this array has 6 values. They are numbered from 0 to 5. Yet you are
looking at coinvalue[6] which is an array overflow.

No. The condition (the second expression in the 'for' statement) has
been executed once at this point, so 'i' actually contains 5. You need
to pay attention to those things...

Gah, you're right. I actually thought of that before I replied, but then
realized that i-- was post and would be decremented after the statement, but
I was thinking the statement block instead of the for statement itself.
That's why I hate that type of code.