#include <iostream.h>
#include <fstream.h>
#include <ctype.h>

//structure record
struct invent
{
	int number, quantity;
	float price;
};

//function prototype
void create();
void display();

void main()
{
	char choice;
	cout << "         Menu Choice\n";
	cout << "A. Create a file\n";
	cout << "D. Display Data and Total Inventory\n\n";
	cout << "Select either A or D ";
	cin >> choice;
	switch (toupper(choice))
	{
	case 'A': create();
		break;
	case 'D': display();
		break;
	default: cout << "Error\n\n";
	}
}//end main
void create()
{
	ofstream outfile;
	invent inventory;
	outfile.open("data.dat");
	cout << "Enter item number or -1 to quit ";
	cin >> inventory.number;
	while (inventory.number != -1)
	{
		cout << "Enter quantity and price separated with a space ";
		cin >> inventory.quantity >> inventory.price;
		outfile << inventory.number << " " << inventory.quantity << " "
				<< inventory.price << endl;
		cout << "Enter item number or -1 to quit ";
		cin >> inventory.number;
	}
	outfile.close();
}//end create
void display()
{
	ifstream infile;
	invent inventory;
	float total=(float)0.0;
	infile.open("data.dat");
	cout << "\nInv number   Quantity   Price\n\n";
	infile >> inventory.number >> inventory.quantity >> inventory.price;
	while (!infile.eof())
	{
		total += inventory.price * inventory.quantity;
		cout << "      " << inventory.number << "        " 
			 << inventory.quantity << "        $"
			 << inventory.price << endl;
	infile >> inventory.number >> inventory.quantity >> inventory.price;
	}
	infile.close();
	cout << "\nTotal inventory $" << total << endl<<endl;
}//end display
/* Answer
         Menu Choice
A. Create a file
D. Display Data and Total Inventory

Select either A or D d

Inv number   Quantity   Price

      20        400        $5
      30        550        $9
      45        600        $20

Total inventory $18950
*/