//Program 9

#include <iostream>
#include <cstring>
#include <fstream>

#define SZ 10

using namespace std;

class Account
{
	char name[30];
	int account_no;
	float balance;
	
	public:
		Account()
		{
			name[0] = '\0';
			account_no = 0;
			balance = 0;
		}
		
		void set(int num, char n[], float b = 0)
		{
			strcpy(name, n);
			account_no = num;
			balance = b;
		}
		
		void display()
		{
			cout<<"\n\nAccount number : "<<account_no
				<<"\nName : "<<name
				<<"\nBalance : "<<balance<<endl;
		}
		
		void deposit()
		{
			float b;
			cout<<"\nEnter amount to be deposited : ";
			cin>>b;
			balance += b;
			cout<<"\nNew balance :"<<balance<<endl;
		}
		
		void withdraw()
		{
			float b;
			cout<<"\nEnter amount to be withdrawn : ";
			cin>>b;
			if(b >= balance)
				cout<<"\nNot enough balance to withdraw from this account.\n";
			else
			{
				balance -= b;
				cout<<"\nNew balance :"<<balance<<endl;
			}
		}
};

int main()
{
	Account acc[SZ];
	int i, a, acnum = 0, choice = 4;
	char name[30], reply = 'y';	
	
	do
	{
		cout<<"\nMenu : "
			<<"\n1.Create a new account."
			<<"\n2.Work with an existing account."
			<<"\n3.Display details of an account."
			<<"\n4.Quit"
			<<"\nYour choice here : ";
		while(!(cin>>choice) || choice < 0 || choice > 4)
			cout<<"\nInvalid choice. Enter again : ";
			
		switch(choice)
		{
			case 1: if(acnum >= SZ)
					{
						cout<<"\nCannot store more accounts.";
						break;
					}
					cout<<"\nEnter name :";
					cin.clear();
				   cin.ignore(1, '\n');
					cin.getline(name,30);
					acc[acnum].set(acnum + 1000, name);
					acc[acnum].deposit();
					cout<<"\nAccount created successfully.\nAccount details : ";
					acc[acnum].display();
					acnum++;
					break;
			
			case 2:	cout<<"\nEnter account number : ";
					cin>>a;
					if(a-1000 >= acnum || a < 1000)
					{
						cout<<"\nSuch an account does not exist.";
						break;
					}
					cout<<"\nYour account is : ";
					acc[a-1000].display();
					cout<<"\nEnter \"1\" to deposit or any other number to withdraw.";
					cin>>i;
					if(i == 1)
						acc[a-1000].deposit();
					else
						acc[a-1000].withdraw();
					break;
					
			case 3: cout<<"\nEnter account number : ";
					cin>>a;
					if(a-1000 >= acnum || a < 1000)
					{
						cout<<"\nSuch an account does not exist.";
						break;
					}
					cout<<"\nYour account is : ";
					acc[a-1000].display();
					break;
					
			case 4: cout<<"\nWriting saved data to file \"ACCOUNTS.TXT\"";
					fstream file;
					file.open("ACCOUNTS", ios::in | ios:: out);
					for(i = 0; i < acnum; i++)
						file.write((char*)&acc[i], sizeof(acc[i]));
					cout<<"\nPress ENTER to view contents of ACCOUNTS.TXT.";
					getchar();
					getchar();
					file.seekg(0);
					Account a;
					for(i = 0; i < acnum; i++)
					{
						file.read((char*)&a, sizeof(a));
						a.display();
						cout<<"\n\n";
					}
					file.close();
		}
	}while(choice != 4);
	system("pause");
	return 0;
}