CS204-Homework 2 Customer Carts Solved

The aim of this homework is to get familiar with basic manipulation with pointers and simple/doubly linked lists, such as: finding (searching for) a node in a list, dynamically adding/deleting a node in a list, creating new list, printing a list, printing a certain node in a list, as well as cooperation of both of those kinds of lists when building a more complex frameworks of linked lists of (doubly) linked list. Your job here is to implement a system for an E-commerce Store. The system will store customer’s carts and the items inside. The following operations must be implemented:

  

1.      Add item to the carts of customers,

2.      Remove item from customer’s cart,

3.      Add a customer,

4.      Remove a customer,

 

as well as extra operations given below. Since neither the number of customers, nor the items they will purchase are known beforehand, we will have to manage this data structure dynamically. Thus, you will dynamically allocate (this is covered in the lectures) and free memory (this is in the slides and will be covered on Monday) during runtime, in accordance to your needs. This means that you are going to use the new statement when allocating a block of memory from the heap and the delete statement when freeing a memory block you won’t need anymore. Pay attention to avoid memory leaks (unused memory which has not been freed) as well as accessing already freed (deleted) memory chunks.  

 

 

 

 

 

 

 

 

Input file
 

The input file is shown below: A record for a customer starts with # proceeded by his/her unique ID (e.g., #189754). After a comma, the customer’s full name is given (e.g. Georges Politzer). Then after a colon (:), the item(s) in her/his cart are given, each in a single row, until a full stop is reached. The items are separated by a comma. Each item starts with a unique integer ID (e.g., 5355). After an empty space, the name of item is given (e.g. Pen). In the end, the amount the customer wants to buy from that item is given in parenthesis (e.g. (2)).  

 

 

 

 

Data structure
 

In the beginning, you are asked to extract the data from the input file and construct a data structure consist of single linked lists of products in the cart on a doubly linked lists of customers, as it is illustrated in the figure below.  

 

 

 

For each Product node, you are asked to store its ID (int), product’s name (string) and amount (int) of it. For each customer, you should store customer’s unique ID (int) and his/her full name (string).  

 

Both the customer’s linked list and product linked list for each customer should always be sorted (say in ascending order) with respect to the IDs of either customers’ or products’. Note that there can be multiple customers with the same name and surname, but all customers will have a different ID. Knowing that there might be thousands of customers, maintaining a sorted doubly linked list for customers at any stage would improve performance when searching for and/or editing certain customer’s data. We expect from you to utilize this fact when writing your assignment. In addition, a doubly linked list will be useful when you are requested to print the customers in reverse order.   

 

The main menu
Below we give to you the node structure for the doubly and the single linked list. We also show to you a print screen of the main menu, as well as a part of code of the main menu. It should give you a clue how to proceed with each menu option and the corresponding function that implements the option. Of course, you preserve the freedom to add/delete/change functions as you wish, given that the output is the desired one.    

 

struct Product { 

       int prod_id;   string prod_name;   int amount;   Product * next; 

}; 

struct Customer{ 

       int cust_id;   string cust_name;   Customer * prev; 

       Customer * next; 

       Product * prod; 

}; 

 

  

         cout << endl; 

         cout << "***********************************************************************" << endl            << "**************** 0 - EXIT PROGRAM                          ************" << endl 

            << "**************** 1 - PRINT ALL CUSTOMER DATA               ************" << endl 

            << "**************** 2 - FIND A CUSTOMER                       ************" << endl 

            << "**************** 3 - ADD A CUSTOMER                        ************" << endl 

            << "**************** 4 - DELETE A CUSTOMER                     ************" << endl 

            << "**************** 5 - ADD A PRODUCT TO A CUSTOMER           ************" << endl 

            << "**************** 6 - DELETE A PRODUCT FROM A CUSTOMER      ************" << endl 

  << "**************** 7 - LIST THE BUYERS OF A PRODUCT          ************" << endl   << "***********************************************************************" << endl;  cout << endl; 

         int option; 

         cout << "Pick an option from above (int number from 0 to 7): ";   cin option; 

         switch (option) 

         { 

         case 0: 

                  cout << "PROGRAM EXITING ... " << endl;            system("pause");            exit(0);         case 1: 

                  print_customer_data(head); 

           break;   case 2: 

                  find_customer(head); 

           break;   case 3: 

           add_customer(head);            break;   case 4: 

                  delete_customer(head); 

           break;   case 5: 

           add_product(head);            break;   case 6: 

           delete_product(head);      break;   case 7: 

                  list_product_owners(head); 

           break;   default: 

                  cout << "INVALID OPTION!!! Try again" << endl; 

         } 

}  

 

Below we describe each of the main menu options (with option 0 being obvious and already implemented).

 

1) Print All Customer Data
It prints all the recorded customers and their corresponding products in the cart to. The output should be as shown below

 

   

  

2) Find A Customer
This feature should allow the user to search for and find a customer (if he/she exists). The search should be done using either the customer’s ID or her/his name.

If a customer is not found, a proper text is printed and the program should send us back to the main menu, as it is shown bellow. Note: Search will be case sensitive, which means Arthur and ARTHUR is not the same.  

 

  

 

If a search is done giving the name&surname of the customer we want to find, you should take care to give it as a single input (e.g. Frida Kahlo in this case should be taken as a single string). (Hint: use getline(cin, name)). If the customer is found, his/her information is printed in the following manner

 

  

 

Since there might be 2 customer with the same name, if user searches with name and surname, you should print all the customers with the same name and surname.

 

   

Remember that search by name is case sensitive.

 

   

3) Add A Customer
This option adds a new customer in the list. It first asks for the new customer’s ID (an integer). Knowing that ID’s are unique, if an already existing ID is entered, a proper message is displayed and the user is returned in the main menu.

 

  

 

If a unique ID is entered, the program asks for the customer’s full name and surname (again, given as a single line parameter with multiple parameters).  After customer is inserted to the list, a proper must be displayed.

 

    

4) Delete A Customer
Deleting is exclusively done by ID (since there might more customer with the same name and surname). If an entered ID doesn’t exist a proper message is shown and program prints the main menu. If the ID is found, firstly products in the customer’s cart are deleted and then his node. In the end a proper message is shown (given below). The newly freed memory should be added to the heap.

 

   

5) Add a Product
First a prompt is shown asking for the customer’s ID. If it doesn’t exist, the user is returned to the main menu. If it exists the user is asked whether she/he wants to add a product to the customer’s cart by choosing (Y/y) for yes or any character for no. If yes is chosen another prompt asks from the user to give the ID of the product she/he wants to add. If it already exists, a message is displayed telling this, as it is shown below, and the amount of product will be increased. If the ID of product doesn’t exist, the user is asked to also give product’s name (as a single line string) and afterwards the product is added to the customer. The (Y/y) is repeated after each attempt to add an product. This is illustrated in the figure below. You can assume the inputs will be correct.

 

   

6) Delete A Product
Firstly, the user is asked to enter the ID of the customer we wish to delete a product for. If it doesn’t exist, we are sent back to the main menu. If it exists, the ID of the product we wish to delete is asked. If it doesn’t exist, we are returned to the main menu. Those scenarios are shown below.

 

  

 

If an existing customer ID and product ID are entered, the product will be deleted, a proper message will be shown and the user will be send to the main menu, as it is shown below

 

  

 

 

7) List the Buyers of a Product
A prompt asking for product ID will be shown in the beginning. If there is a product for the entered product ID, the customers who has the product in their carts should be printed with the amounts in their cart. Printing will be in reverse order with respect to IDs of customers. If there is no product for the given ID, a proper message should be displayed. Those cases are illustrated below.