Question: Classes and array of pointers

[Kbott]

So I am working on a program that asks the following:

Define a ShoppingCart class which contains as a data member an array of pointer-to-Item (Item*) that can contain up to 100 Item pointers

The array would be in a separate shoppingcart.hpp and shoppingcart.cpp and I am not sure how to do this or what it should look like.
I have read over this
http://www.cplusplus.com/forum/general/52820/
and this
http://www.cplusplus.com/forum/beginner/49103/

however I am not much further along.

.cpp code

#include <iostream>
#include <string>
#include <cmath>
#include "Item.hpp"

using namespace std;

Item::Item()
{
   setName("");
   setPrice(0.0);
   setQuantity(0);
}

Item::Item(string lable, double cost, int number)
{

   setName(lable);
   setPrice(cost);
   setQuantity(number);

}

void Item::setName (string lable)
{
   name = lable;
}

void Item::setPrice(double cost)
{
   price = cost;
}

void Item::setQuantity(int number)
{
   quantity = number;
}

string Item::getName()
{
   return name;
}

double Item::getPrice()
{
   return price;
}

int Item::getQuantity()
{
   return quantity;
}

.hpp code

#include <string>
#ifndef ITEM_HPP
#define ITEM_HPP

class Item
{
   private:
      std::string name;
      double price;
      int quantity;

      public:
      Item();
      Item(std::string, double, int);
      void setName (std::string);
      void setPrice(double);
      void setQuantity(int);
      std::string getName();
      double getPrice();
      int getQuantity();


};
#endif 

#include "ShoppingCart.hpp"
#include <iostream>


ShoppingCart::ShoppingCart(Item,Item)
{
   arrayEnd = 0;
   for(int i = 0; i<100;i++)
   {
	 array[i] = NULL;
   }
}
   
/******************************
 * Description: adds object to the array
 * ***************************/

Item addItem(Item itemArg)
{
   array[arrayEnd] = itemArg; 
   arrayEnd++;

}

/*****************************************
 * Description: calculates the total price of Items * price
 * ****************************************/

Item totalPrice(Item)
{
   Item sum = 0; // keep the running total

   for(int i = 0; i < arrayEnd; i++)
   {
      sum += array[i].getPrice * array[i].getQuantity;
   }
   return sum;
}

cart.hpp

#ifndef ITEM_HPP
#include "Item.hpp"
#include <algorithm>

class ShoppingCart
{
   private:

      Item* array[100];
      int arrayEnd;
      int count;


   public:
      shoppingCart() : count(0)
   {
      std::fill(std::begin(array), std::end(array), nullptr);
   }
      ShoppingCart(Item, Item);
      Item addItem(Item);
      Item totalPrice(Item);

};
#endif 

[coder777]

In order to use the array you need a second variable that contains the amount of items in that array.

Alternatively the amount of items may be detected when there is a nullptr.

Either way you need a constructor for ShoppingCart that initialize the array and the possible count variable.

...
#include <algorithm>    // std::fill
...

class ShoppingCart
{
   private:

      Item* array[100];
      int count;

   public:
      ShoppingCart() : count(0)
      {
            std::fill(std::begin(array), std::end(array), nullptr);
      }
...

[Kbott]

so I am not sure if that helped or if I am missing something. I looked over other project and the setup is slimier. but at the moment I am getting

 ShoppingCart.cpp:26:4: error: ‘array’ was not declared in this scope
    array[arrayEnd] = itemArg;

I will update the code in my first post above.

If they are declared in the constructor why is the rest of the program not seeing them?

ShoppingCart::ShoppingCart(Item,Item)
{
   arrayEnd = 0;
   for(int i = 0; i<100;i++)
   {
	 array[i] = NULL;
   }
}

[coder777]

addItem(...) and totalPrice(...) are free function not members of the class. Add the sope ShoppingCart:: before the function name.


arrayEnd and count are the same, so get rid of one of them.


ShoppingCart(Item,Item) // What is the use of this Item?

You should either use the paramter passed or remove them.