********* Message from Amity Warren **************
Looking at my program another time I realized that the compiler
didn't seem to need my operator overloading =.  I did it for 
the Book class, but didn't do it for the magazine class - and yet 
both yet.  It seems that this is because the compiler automatically
does a binary copy of an object, and so it works. 
Wahoo!

**************************************************
Yes, you don't need the assignment operator in this case, because
the default version created by the compiler works fine.
-hiroya



------------------- DBLIB.CPP follows --------------------
/* Library Book and Magazine Database main file
*  by Amity Warren
*/

#include <fstream.h>
#include <iostream.h>
#include <cstring.h>
#include <assert.h>
#include "dblib.h"

void sorta(Book* X) {
	int status = 1;
	while (status != 0) {
		status = Switcha(X);
	}
}

int Switcha(Book* X) {
	Book temp;
	int switched = 0,
		 i = 0;
	while (i < NUMITEMS - 1) {
		if (X[i].author > X[i + 1].author) {
			temp = X[i];               // swap two values
			X[i] = X[i + 1];
			X[i + 1] = temp;
			switched++;
		}
		i++;  // advance to next book in array
	}
	return switched;
}

int main(int argc, char** argv)
{
	if (argc != 2) {
		cout << "\n Usage: " << argv[0] << " infile\n";
		exit(1);
	}

	ifstream f_in(argv[1]);

	// error checking
	if (!f_in) {
		cerr << "Cannot open file: " << argv[1] << endl;
		exit(1);
	}

	cout << "Book and Magazine Library Database program\n";
	cout << "By Amity Warren \n";

	Book blib[NUMITEMS];
	Magazine mlib[NUMITEMS];
	int i;
	char temp[100];

	cout << "Unordered data set follows: " << endl;
	// read in books
	for (i = 0; i < NUMITEMS; i++) {
		f_in.getline(temp, 100); // throw away, marker line for my benefit
		f_in.getline(temp, 100);
		blib[i].author = temp;
		f_in.getline(temp,100);
		blib[i].title = temp;
		f_in.getline(temp,100);
		blib[i].subject = temp;
		f_in.getline(temp,100);
		blib[i].ISBN = temp;
		blib[i].print();
	}
	// read in magazines
	for (i = 0; i < NUMITEMS; i++) {
		f_in.getline(temp, 100); // throw away, marker line for my benefit
		f_in.getline(temp, 100);
		mlib[i].title = temp;
		f_in.getline(temp,100);
		mlib[i].date = temp;
		f_in.getline(temp,100);
		mlib[i].subject = temp;
		f_in.getline(temp,100);
		mlib[i].ref = temp;
		mlib[i].print();
	}

	cout << "Books sorted by Title" << endl;
	sort(blib);
	for (i = 0; i < NUMITEMS; i++) {
		blib[i].print();
	}
	cout << "\nMagazines sorted by Title" << endl;
	sort(mlib);
	for (i = 0; i < NUMITEMS; i++) {
		mlib[i].print();
	}
	sorta(blib);
	cout << "\nBooks sorted by author" << endl;
	for (i = 0; i < NUMITEMS; i++) {
		blib[i].print();
	}

	cout << "Done";
		return 0;
}

------------------- DBLIB.H follows --------------------
/*  Database header file
*   Homework assignment #4
* 	 By Amity Warren
*/

#ifndef Dblib_h
#define Dblib_h

#define NUMITEMS 8

typedef enum boolean {false = 0, true = 1}boolean;

class Item {
	public:
		string title;
		string subject;
		Item(){};
		Item(const Item &x){}; // implement this
		~Item(){};
		void print() {cout << "\nSubject : "<< subject<< endl << title;}
};

class Book:public Item {
	public:
		string author;
		string ISBN;
		Book(){};
		~Book(){};
		void print();
		Book& operator=(const Book& b);
};

class Magazine: public Item {
	public:
		string date;
		string ref;
		Magazine(){};
		~Magazine(){};
		void print();
};

void Book :: print() {
	Item :: print();
	cout << " by " << author << endl;
	cout << "ISBN : " << ISBN << endl;
}

Book& Book :: operator=(const Book& b)
{
	title = b.title;
	subject = b.subject;
	author = b.author;
	ISBN = b.ISBN;
	return(*this);
}

void Magazine :: print() {
	Item :: print();
	cout << "\nDate published : " << date << endl;
	cout << ref << endl;
}

template<class T> void sort(T* X);
template<class T> int Switch(T* X);

void sorta(Book* X);
int Switcha(Book* b);

template<class T> void sort(T* X) {
	int status = 1;
	while (status != 0) {
		status = Switch(X);
	}
}

template<class T> int Switch(T* X) {
	T temp;
	int switched = 0,
		 i = 0;
	while (i < NUMITEMS - 1) {
		if (X[i].title > X[i + 1].title) {
			temp = X[i];               // swap two values
			X[i] = X[i + 1];
			X[i + 1] = temp;
			switched++;
		}
		i++;  // advance to next book in array
	}
	return switched;
}
#endif