using pointers to arrays in a function

Question

I have declared a 2_D array as

int array [NO_OF_ROWS][NO_OF_COL];

NO_OF_ROWS and NO_OF_COL are constants.

I then have pointers *rowPtr and *seatPtr. I pass all of these to a function so I can save data from a binary file to the array along with an enumerated status as follows

 void loadArray (int* &rowPtr, int* &seatPtr, status& seatStatus,
               status seatArray[][NO_OF_COL])

in the function i try to save the status to the array with the line;

 seatArray[rowPtr][seatPtr] = seatStatus;

when I try to compile I get the error:

invalid types ' status(*)[6][int*] for array subscript

I see that the array does not like the pointer value since it was declared as an int type. How would I set this up to allow the pointer to be used

Why write any of this nonsense instead of using C++? Use std::array or std::vector, and don't use pointers. — Kerrek SB
– Kerrek SB, Commented Dec 3, 2011 at 2:58
Forget everything you know. Learn C++. ^^ . Also 2D arrays are bad. You can do just fine with one array and smart indexing. In addition it may be faster since you only have one level of indirection - if you care about these things anyway.. — FailedDev
– FailedDev, Commented Dec 3, 2011 at 3:02
@KerrekSB Why do you always say people should use STL containers. Their flexibility comes with some price also. You do need to be more careful with pointers, but you've also get a lot in reward. — Roman Byshko
– Roman Byshko, Commented Dec 3, 2011 at 3:03
It's not obvious to me what rowPtr and seatPtr are supposed to represent. Could you post the code-snippet that initializes them? — ruakh
– ruakh, Commented Dec 3, 2011 at 3:04
@FailedDev I've seen a lot of experienced developers here, who after seeing pointers immediately say that STL string or vector should be used. But those are slower and have bigger memory footprint. Shouldn't this also considered? — Roman Byshko
– Roman Byshko, Commented Dec 3, 2011 at 3:08

Mrafcho001 · Accepted Answer · 2011-12-03 03:03:19Z

1

You declared the pointers incorrectly. Try this:

void loadArray (int* rowPtr, int* seatPtr, status& seatStatus,
           status seatArray[][NO_OF_COL])

And then dereference the pointers when you want to use their values as such:

seatArray[*rowPtr][*seatPtr] = seatStatus;

answered Dec 3, 2011 at 3:03

Mrafcho001

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1 Comment

FailedDev Over a year ago

I really doubt the OP understood what you did, or learned anything at all. But +1 nevertheless.

acpluspluscoder · Accepted Answer · 2011-12-03 03:15:52Z

0

Dereference the pointers.

seatArray[*rowPtr][*seatPtr] = seatStatus;

answered Dec 3, 2011 at 3:15

acpluspluscoder

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