Ad:

C++ Discussion Thread
Marked Solved
Views: 3921

You are currently viewing page 4 of this multi-page discussion thread; Jump to the first page

Sep 6th, 2007

Re: passing arrays / updating object arrays

C++ Syntax (Toggle Plain Text)
toppings[z] = a[z] ;
toppings[z] = a[z] ;

If a is declared as a plain int, why are you subscripting it like an array of int? I think you should make the whole thing an array and that'll fix your problem.

C++ Syntax (Toggle Plain Text)
void Pizza::set ( int x , int y , int a[] , int i );
void Pizza::set ( int x , int y , int a[] , int i );

C++ Syntax (Toggle Plain Text)
void Pizza::set ( int x , int y , int a[] , int i )
{
    type = x ;
    size = y ;
    for ( int z = 0 ; z < i ; z++ )
        toppings[z] = a[z] ;
}
void Pizza::set ( int x , int y , int a[] , int i )
{
    type = x ;
    size = y ;
    for ( int z = 0 ; z < i ; z++ )
        toppings[z] = a[z] ;
}

C++ Syntax (Toggle Plain Text)
pizza.set ( x , y , a, i ) ;
pizza.set ( x , y , a, i ) ;

Hamrick

Reputation Points: 180

Solved Threads: 34

Posting Whiz

Offline

322 posts
since Jun 2007

Permalink

Sep 6th, 2007

Re: passing arrays / updating object arrays

awesome!! It's working now!
Now I just need to do some slight modifications and add the computePrice function and I'm done.

thanks everyone!!

Duki

Reputation Points: 817

Solved Threads: 32

Nearly a Posting Virtuoso

Offline

1,474 posts
since Jun 2006

Permalink

Sep 6th, 2007

Re: passing arrays / updating object arrays

I thought you had declared the third parameter as a reference to an array?

C++ Syntax (Toggle Plain Text)
void Pizza::set ( int x , int y , int (&a)[7] , int i )
void Pizza::set ( int x , int y , int (&a)[7] , int i )

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Sep 6th, 2007

Re: passing arrays / updating object arrays

i did but then i found out that c++ passes all arrays by reference by default.

Duki

Reputation Points: 817

Solved Threads: 32

Nearly a Posting Virtuoso

Offline

1,474 posts
since Jun 2006

Permalink

Sep 6th, 2007

Re: passing arrays / updating object arrays

Quote ...

i did but then i found out that c++ passes all arrays by reference by default.

You have to be careful here. 'By reference' could mean two things, and only one of them is right.

Thef irst by reference is an actual reference in C++ and arrays are not passed by that reference by default. To pass an array by actual reference in C++ you do it like Dave said.

C++ Syntax (Toggle Plain Text)
void Pizza::set ( int x , int y , int (&a)[7] , int i )
void Pizza::set ( int x , int y , int (&a)[7] , int i )

The second by reference is a fake reference that you get by passing a pointer by value and being able to get to the thing that the pointer points to. That's the default for arrays and that's why all of these are the same prototype.

C++ Syntax (Toggle Plain Text)
void Pizza::set ( int x , int y , int a[7] , int i )
void Pizza::set ( int x , int y , int a[] , int i )
void Pizza::set ( int x , int y , int *a , int i )
void Pizza::set ( int x , int y , int a[7] , int i )
void Pizza::set ( int x , int y , int a[] , int i )
void Pizza::set ( int x , int y , int *a , int i )

Woohoo! Finally something I know something about.

Last edited by Hamrick; Sep 6th, 2007 at 10:20 pm.

Hamrick

Reputation Points: 180

Solved Threads: 34

Posting Whiz

Offline

322 posts
since Jun 2007

Permalink

Sep 7th, 2007

Re: passing arrays / updating object arrays

ah ok. so did i create a pointer?

Duki

Reputation Points: 817

Solved Threads: 32

Nearly a Posting Virtuoso

Offline

1,474 posts
since Jun 2006

Permalink

Sep 7th, 2007

Re: passing arrays / updating object arrays

The answer depends on the current code.

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Sep 7th, 2007

Re: passing arrays / updating object arrays

it's the same as post #31.

Duki

Reputation Points: 817

Solved Threads: 32

Nearly a Posting Virtuoso

Offline

1,474 posts
since Jun 2006

Permalink

Sep 7th, 2007

Re: passing arrays / updating object arrays

That's a pointer (see #35).
http://c-faq.com/aryptr/aryptrparam.html

Last edited by Dave Sinkula; Sep 7th, 2007 at 12:33 am.

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Previous
1
2
3
Page 4

This thread is solved

Either the thread starter or a moderator has marked this thread as solved. You can most likely trust the responses and answers given. There is most likely no reason for any further responses to be posted here. If you have a related question, please start a new thread in this forum instead.

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C++ Forum Timeline: Pls Help

Next Thread in C++ Forum Timeline: Dynamic array

DaniWeb Message

Cancel Changes

User Name
Password