/*-----
  Signature: main: void -> int

  Purpose: to demonstrate a dynamically-allocated array
  
  Examples: When called, if when prompted the user enters
3
  and then
15
20
13
  then the following will be printed to the screen:
15
20
13

  by: Sharon Tuttle 
  last modified: 12-3-10
-----*/

#include <iostream>
using namespace std;

int main()
{
    // local variables

    int *quant_array_ptr; // LOOKS like a pointer to an int --
                             //    BUT we'll set up to point to
                             //    an int ARRAY, instead;
    int num_quants;

    // how big shall the quantity array be?

    cout << "how many quantities are there? ";
    cin >> num_quants;

    // now I want to dynamically allocate an array of ints
    //    of that size

    quant_array_ptr = new int[num_quants];

    // and now, I can STILL use the array notation I'm used to!
    // ...for example, to interactively fill the array;

    for (int i=0; i<num_quants; i++)
    {
        cout << "what is the next quantity? ";
        cin >> quant_array_ptr[i];
    }

    // COULD do other stuff here, if desired;
    
    // prove it has been filled/see what's in the array now

    for (int i=0; i < num_quants; i++)
    {
        cout << quant_array_ptr[i] << endl;
    }

    // but BE CAREFUL!!! to FREE the dynamically-allocated
    //     array, you need to use SPECIAL SYNTAX!!!!!
    // (compiler needs a clue to deallocate a whole array,
    //     not just a single value...)

    delete [ ] quant_array_ptr;

    quant_array_ptr = NULL;     // good style: set to NULL
                                //    after you deallocate what
                                //    it points to...!
                                // (although not QUITE as vital if
                                //    the delete is the LAST line of
                                //    the function...)

    return EXIT_SUCCESS;
}