#include <fstream.h>
#include <string.h>

class daf
{
	public:
		GetFilename();
		OpenFileForOutput();
		CloseOutputFile();
		OpenFileForInput();
		CloseInputFile();
		GetDataFromUser();
		Print();
		ReadRecord();
		WriteRecord();
		FileLength();
		Clear();
	private:
		struct part
		{	int partNo;
			char item[30];
		};
		part theData;
		char filename[20];
		ofstream out;
		ifstream in;
};
daf::OpenFileForOutput()
{
	out.open(filename, ios::out | ios::binary);
	if (!out)
	{	cout << "File open failed\n";
		return 1;
	}
}
daf::CloseOutputFile()
{
	out.close();
}
daf::OpenFileForInput()
{
	in.open(filename, ios::in | ios::binary);
	if (!in)
	{	cout << "File open failed\n";
		return 1;
	}
}
daf::CloseInputFile()
{
	in.close();
}
daf::Clear()
{
	theData.partNo = 0;
	strcpy(theData.item, " ");
}
daf::Print()
{
	cout << "Part Number: " << theData.partNo << endl;;
	cout << "Item Name: " << theData.item << endl;;
}
daf::ReadRecord()
{
	int rec;
	cout << "Part Number to access: "; 
	cin >> rec;
	cout << "trying to find record number " << rec << endl;
	cout << "Seeking to position " << rec*sizeof(struct part) << endl;
	in.seekg(rec*sizeof(struct part), ios::beg);
	in.read((unsigned char *) &theData, sizeof(struct part));
}
daf::WriteRecord()
{
	cout << "Seeking to position " << theData.partNo * sizeof(struct part) << endl;
	out.seekp(theData.partNo * sizeof(struct part), ios::beg);
	out.write((unsigned char *) &theData, sizeof(struct part));
}
daf::GetFilename()
{
	cout << "Please enter name of file: ";
	cin >> filename;
}
daf::GetDataFromUser()
{
	cout << "Please enter part no: ";
	cin >> theData.partNo;
	cout << "Please enter name of item: ";
	cin >> theData.item;
}