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Aug 20th, 2005

Pointers and Dynamic Arrays

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I am having problems with the most important section of this program. I must admit after reading, I understand the concept, but applying it to this particular program is not coming through. I am attaching the source code but the portion I am having problems with is the following:

void add_item(double number)

What I am trying to do is also attached in the sample snapshot. I know what I need to do but have a hard time implementing. I know I should add entries until it reaches the max. Once it is at the max, add the next one but double the maximum. I hope someone can help.

Attached Files

	assignment6b1.cpp (4.4 KB, 31 views)
	assign6b_2_sample_output.doc (195.5 KB, 29 views)

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konacious

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Aug 20th, 2005

Re: Pointers and Dynamic Arrays

In your solution void add_item(double number) should be a member of the class.

It should be defined using

void List::add_item(double number) outside the class

Also I noticed that you never use the number parameter within the add_item method.

Does your progam compile?

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Programming ( Assignment / Project ) Help

proghelper

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Aug 20th, 2005

Re: Pointers and Dynamic Arrays

in the default constructure allocate the array with max number of doubles.

function add_item is all f**ked up. change the name to list::add_item and delete all its contents.

if size == MAX_LIST_SIZE then reallocate the array, otherwise just insert the new number into list[size++];

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Aug 21st, 2005

Re: Pointers and Dynamic Arrays

void list::add_item(double number)
{
ArrayPtr *m = new ArrayPtr double [d1];
delete [m];
int i, d1, d2;

if size = MAX_LIST_SIZE
{
for (i = 0; i < d1; i++)
m[i] = new int[d2]

}
else
{
list [size] = number;
size++;
}
}

I'm not getting it. Once I check the size, add it and then count.....else just add the record???

konacious

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Aug 21st, 2005

Re: Pointers and Dynamic Arrays

C Syntax (Toggle Plain Text)
void list::add_item(double number)
{
	if (size == max )
	{
               // reallocate the array 
               ArrayPtr m = new ArrayPtr [max + MAX_LIST_SIZE];
              // copy existing data into new array
               memcpy(m, list, size * sizeof(double));
              // delete old array object
              delete[] list;
              // reset list
              list = m;
              // bump array size
              max += MAX_LIST_SIZE;
        }
       // add number to the list
	list [size] = number;
	size++;
}
void list::add_item(double number)
{
	if (size == max )
	{
               // reallocate the array 
               ArrayPtr m = new ArrayPtr [max + MAX_LIST_SIZE];
              // copy existing data into new array
               memcpy(m, list, size * sizeof(double));
              // delete old array object
              delete[] list;
              // reset list
              list = m;
              // bump array size
              max += MAX_LIST_SIZE;
        }
       // add number to the list
	list [size] = number;
	size++;
}

I'm not getting it. Once I check the size, add it and then count.....else just add the record???[/QUOTE]

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