// John Doe
// function demo
// day of week??

#include <iostream>
#include <cstdlib>
using namespace std;

// ************** function declaration statements ******************
void displayMenu();
void displayReceipt(double amount);

// ******************* constant declaration statements *******
const double BOOK_PRICE = 9.00;   // price per book

int main()
{
   // *************** variable declaration statements *******
   int numBooks = 0;               // # of books for this order
   int totalNumBooks = 0;          // total # of books ordered by customer
   double bookSubtotal = 0.0;      // subtotal cost of books
   bool userWantsToExit = false;   // flag variable to exit while loop
   int menuChoice = 0;             // customer's menu choice

   while (!userWantsToExit)
   {	
      displayMenu();

      cout << "Enter your choice: ";
      cin >> menuChoice; 

      if (menuChoice == 1)
      {
         cout << "Enter number of books: ";
         cin >> numBooks;

         if (numBooks >= 0 && numBooks <= 10)
         {
            totalNumBooks += numBooks;
         }
         else
         {
            cout << "Invalid input." << endl;
         }

      }
      else if (menuChoice == 2)
      {
         // movie inputs & calculations here
      }
      else if (menuChoice == 3)
      {
         // peanuts inputs & calculations here
      }
      else if (menuChoice == 4)
      {
         userWantsToExit = true;	
      }
      else
      {
         cout << "Invalid input." << endl;
      }

      bookSubtotal = totalNumBooks * BOOK_PRICE;
   }

   // *************** output display ************************
   displayReceipt(bookSubtotal);
		
   system("pause");
   return 0;
}// end of main

//////////////////// FUNCTIONS ////////////////////////////////

void displayMenu()
{
    cout << "1 Books" << endl;
    cout << "2 Movies" << endl;
    cout << "3 Peanuts" << endl;
    cout << "4 Checkout" << endl;
}// end of displayMenu

//////////////////////////////////////////////////////////////

void displayReceipt(double amount)
{
    cout << endl << endl << endl;
    cout << "******************************************" << endl;
    cout << "***   THANK YOU FOR SHOPPING AT ACME   ***" << endl;
    cout << "******************************************" << endl;
    cout << "Total:          $" << amount << endl;
    cout << endl << endl << endl;
}// end of displayReceipt