// MENU.CPP
//
// This program illustrates the use of simple one-character
//   commands.  The program displays a menu, accepts a command
//   and executes it.  The application is an embryonic
//   "Inventory Control System" which, at this stage of development,
//   only maintains a list of "inventory items" (integers).
//   Items are stored in an integer array. The "quantity" is
//   not supported -- it is set to 1 for all inventory items.
//
// Author: Bill Wares
//

#include <iostream.h>
#include <iomanip.h>
#include <ctype.h>                 // Declares toupper(ch)
#include "apvector.h"

const int QUANTITY = 1;        // Quantity for each item is set
                               //   to 1 in this preliminary version.

// Function prototypes:

int Find (const apvector<int> &inventory, int partNum);
void Show (const apvector<int> &inventory, int partNum);
void Add (apvector<int> &inventory, int partNum);
void Remove (apvector<int> &inventory, int partNum);
void List (const apvector<int> &inventory);

//****************************************************************
//****************             main            *******************
//****************************************************************

int main()

{
    apvector<int> inventory;   // Array of items (initially empty)
    char cmd;
    int partNum;

    cout << "\n          One Of Each, Inc.\n";
    cout << "      Inventory Control System\n";

    for(;;) {  // Repeat (until break)

        // Show the menu and prompt:

        cout << "\n";  // Output a blank line

        cout << "\t (S)how inventory item\n";      // '\t' is tab
        cout << "\t (A)dd item\n";
        cout << "\t (R)emove item\n";
        cout << "\t (L)ist inventory\n";
        cout << "\t (Q)uit\n";
        cout << endl;
        cout << "Next command ==> ";

        // Accept command:

        cin >> cmd;             // Read one char.
        cin.ignore(80, '\n');   // Skip remaining input (up to 80
                                //   chars) to the end of the line.
        cmd = toupper(cmd);     // Convert letter to upper case
                                //   to allow lower case input
                                //   for commands (for convenience).

        // Quit if 'Q'

        if (cmd == 'Q')
            break;                  // Quit processing commands

        cout << "\n\n****************************************\n";

        // Process command:

        switch (cmd) {

          case 'S':           // Show inventory item information

            cout << "Part number: ";
            cin >> partNum;
            Show(inventory, partNum);
            break;

          case ...
          ...
          ...
 
        }

        cout << "****************************************\n";
    }
    return 0;
}

//****************************************************************
//****************          Functions          *******************
//****************************************************************

int Find (const apvector<int> &inventory, int partNum)

// Finds the part number, partNum, in the inventory array.
// Returns its index if found, -1 otherwise.

{
    int i, nItems = inventory.length();

    for (i = 0;   i < nItems;   i++)
        if (inventory[i] == partNum)
            return i;
    return -1;
}

//****************************************************************

void Show (const apvector<int> &inventory, int partNum)

// Displays inventory information for the given part number.

{
    ...
    ...
}

//****************************************************************

void Add (apvector<int> &inventory, int partNum)

// Adds the new inventory item with the specified part number,
//   partNum, to the inventory list.
//   Checks whether partNum is already in the list.

{
    int nItems;

    if (Find(inventory, partNum) >= 0)
        cout << "already registered in the inventory list.\n";
    else {
        nItems = inventory.length();
        inventory.resize(nItems+1);
        inventory[nItems] = partNum;
        cout << "added to the inventory list.\n";
    }
}

//****************************************************************

void Remove (apvector<int> &inventory, int partNum)

// Removes the item partNum from the inventory list, if it
//   is there.  Displays an appropriate message if partNum is not
//   in the list.

{
    int i, j, nItems;

    i = Find(inventory, partNum);
    if (i < 0)
        cout << "not found.\n";
    else {
        nItems = inventory.length();
        for (j = i+1;   j < nItems;   j++)  // Shift items
            inventory[j-1] = inventory[j];  //  to fill the gap.
        inventory.resize(nItems - 1);
        cout << "removed from the inventory list.\n";
    }
}

//****************************************************************

void List (const apvector<int> &inventory)

// Displays the inventory list.

{
    ...
    ...
}