///////    File Account.java    ///////

public class Account     // class name
{ 
    public Account(int id, double amt) // constructor
    {     acct_no = id;
          acct_bal = amt;
    }
    public double balance()
    {    return(acct_bal);   }

    public void deposit(double amt)
    {    if ( amt > 0 ) acct_bal += amt;   }

    public int withdraw(double amt)
    {    if( amt <=0 || amt > acct_bal )
             return(-1);              // failure
         acct_bal -= amt;
         return(0);
    }

    public int id()
    {    return acct_no;  }

    public int transfer(double amt, Account target)
    {    if( amt > target.acct_bal )
             return(-1);              // failure
         target.acct_bal -= amt;      // charge target account (a)
         acct_bal += amt;             // credit host account
         return(0);                   // success
    }

// private data members
    private int       acct_no;        // account number
    private double    acct_bal;       // current balance
}