Question

Write a program that uses a structure to store the following inventory information in a Binary file and access it using Random Access Method: Item description Quantity on hand Wholesale cost Retail cost Date added to inventory The program should have a menu that allows the user to perform the following tasks: Add new records to the file Display any record in the file Change any record in the file For exact menu option text please see the test cases below

Answer 1

Solution

Code

#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <cctype>
using namespace std;

struct Inventory
{
   string description,Date;  
   int quantity;          
   double wholesalecost, RetailCost;  
};

void addnewrecord(Inventory &, fstream &);
void displayanyrecord(Inventory &, fstream &);
void changeanyrecord(Inventory &, fstream &);
long byteNum(int);
void showerror();
bool checkdate(string);

int main ()
{
   Inventory record;
   int Input;

   fstream File("inventory.dat", ios::out | ios::in | ios::binary);
   if (!File)
   {
       cout << "Error opening file.\n";
       return 0;
   }

   cout << " Inventory \n"
       << "Choose othe option:\n";
   cout << " 1. Adding new records to the file.\n";
   cout << " 2. Displaying any record in the file.\n";
   cout << " 3. Changing any record in the file.\n";
   cin >> Input;

   switch (Input)
   {
       case 1 : addnewrecord(record, File);
               break;
       case 2 : displayanyrecord(record, File);
               break;
       case 3 : changeanyrecord(record, File);
   }

   File.close();
   return 0;
}

void addnewrecord(Inventory &record, fstream &File)
{
   File.seekp(0L, ios::end);
   cout << "Enter the following inventory information:\n";
   cout << "Item description: ";
   cin.ignore();
   getline(cin, record.description);
   do
   {
       cout << "Date in the format MM/DD/YYYY: ";
       cin.ignore();
       getline(cin, record.Date);

       if (checkdate(record.Date) == 0)
       {
           cout << checkdate(record.Date) << endl;
           cout << "Error! Invalid date format.\n";
       }

   } while (checkdate(record.Date) == 0);
   do
   {
       cout << "Quantity :";
       cin >> record.quantity;
       if (record.quantity < 0)
           showerror();
   } while (record.quantity < 0);
   do
   {
       cout << "Wholesale cost: ";
       cin >> record.wholesalecost;
       if (record.quantity < 0)
           showerror();
   } while (record.wholesalecost < 0);
   do
   {
       cout << "Retail cost: ";
       cin >> record.RetailCost;
       if (record.RetailCost < 0)
           showerror();
   } while (record.RetailCost < 0);
   File.write(reinterpret_cast<char *>(&record), sizeof(record));
}

void displayanyrecord(Inventory &record, fstream &File)
{
   int recNum;

   cout << "Enter the record number: ";
   cin >> recNum;
   if (recNum < 1)
       recNum = 1;
   recNum--;
   File.seekg(byteNum(recNum), ios::beg);
   File.read(reinterpret_cast<char *>(&record), sizeof(record));
   cout << "Record number: " << (recNum + 1) << endl;
   cout << "Item description: ";
   cout << record.description << endl;
   cout << "Date : ";
   cout << record.Date << endl;
   cout << "Quantity :";
   cout << fixed << showpoint << setprecision(2);
   cout << record.quantity << endl;
   cout << "Wholesale cost: ";
   cout << record.wholesalecost << endl;
   cout << "Retail cost: ";
   cout << record.RetailCost << endl;
}

void changeanyrecord(Inventory &record, fstream &File)
{
   int recNum;

   cout << "Enter the record number: ";
   cin >> recNum;
   if (recNum < 1)
       recNum = 1;
   recNum--;
   File.seekg(byteNum(recNum), ios::beg);
   File.read(reinterpret_cast<char *>(&record), sizeof(record));
   cout << "Enter the following inventory information:\n";
   cout << "Item description: ";
   cin.ignore();
   getline(cin, record.description);
   do
   {
       cout << "Date in the format MM/DD/YYYY: ";
       cin.ignore();
       getline(cin, record.Date);
       if (!checkdate(record.Date))
       {
           cout << checkdate(record.Date) << endl;
           cout << "Error! Invalid date format.\n";
       }
   } while (!checkdate(record.Date));
   do
   {
       cout << "Quantity :";
       cin >> record.quantity;
       if (record.quantity < 0)
           showerror();
   } while (record.quantity < 0);
   do
   {
       cout << "Wholesale cost: ";
       cin >> record.wholesalecost;
       if (record.quantity < 0)
           showerror();
   } while (record.wholesalecost < 0);
   do
   {
       cout << "Retail cost: ";
       cin >> record.RetailCost;
       if (record.RetailCost < 0)
           showerror();
   } while (record.RetailCost < 0);
   File.seekp(byteNum(recNum), ios::beg);
   File.write(reinterpret_cast<char *>(&record), sizeof(record));
}

long byteNum(int recNum)
{
   return sizeof(Inventory) * recNum;
}

void showerror()
{
   cout << "Error the number should be greater than 0.\n";
}

bool checkdate(string date)
{
   if ( date.length() == 9)
       date = "0" + date;

   if (date.length() != 10)
       return false;
  
   for (int i = 0; i < date.length(); i++)
   {
       if (i == 2 || i == 5)
       {
           if (date[i] != '/')
           {
               return false;
           }
           continue;
       }

       if (!isdigit(date[i]))
           return false;
   }
   return true;
}

Screenshot

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