Array of pointers

[sundar0206]

Hi
I am current ly using dynamically allocated pointers in a little simulation I am coding .

    pos.Initialize(3,0,3);
    TEnt* a=new TEnt(pos);

What it does is initialize a position and creates a new instance.

I now want to test my simulation with a large number of entities in which case it becomes hard for me to instance it one by one
How does a array of pointers work. Can someone give me a example ?

(I need to have a randomly choosen position for each of the entity )

[Etherous]

First of all, it sounds like you want your 'array' to be of dynamic length. If this is the case, I highly recommend you use a vector instead of array. If using an array, you might do something like this:

// Creates the array
// Have MAX_LIST_LENGTH defined beforehand, or just use literal here:
TEnt list[MAX_LIST_LENGTH]; // ahoodin is right. put * symbol between 'TEnt' and 'list' on this line
// loop through the array, creating and adding elements
for(int i = 0; i < MAX_LIST_LENGTH; i++)
{
    pos.Initialize(x,y,z);
    list[i] = new TEnt(pos);
}

However, if you decide to use a vector, it might look something like this:

#include <vector>
...
std::vector<TEnt> list;
for(int i = 0; i < NUMBER_OF_ITEMS; i++)
{
    pos.Initialize(x,y,z);
    list.push_back(*(new TEnt(pos)));
}

Or, I could be totally off base here. Let me know if this helps.

Edit: ahoodin (below) is right. I forgot we were working with pointers. Simply add the * symbol in that case.

[Etherous]

Also, I put x, y, and z in my code example. But you would likely replace those with whatever function is generating your random positions.

[ahoodin]

Well if you don't change your syntax to use STL, which you may or may not care to do, i have come a few questions that should answer your questions:

Q1: How do I declare an array of pointers:

TEnt *a[nMax];

or

TEnt *a[] = {TEnt1,TEnt2,TEnt3,TEnt4};

Q2: How do you initialize an array of pointers

for (n = 0; n < nMax; n++)
           a[n] = new TEnt(pos);

or:

TEnt *a[] = {TEnt1,TEnt2,TEnt3,TEnt4};

Q3: How do I dereference an element of a pointer array (one of the pointers):

*a[5]

Q4: How else should I manage an array of pointers:

for (n = 0; n < nMax; n++)
           delete a[n]

but only after your done with them.

[sundar0206]

Thanks for the reply...
works great

[ahoodin]

Glad to help. Which post helped?
Update should be either:

TEnt *a[] = {&TEnt1,&TEnt2,&TEnt3,&TEnt4};

TEnt *a[] = {pTEnt1,pTEnt2,pTEnt3,pTEnt4};

where pTEnt1 is a pointer to TEnt1.