Question

Question: An ATM can only dispense bills of the following denominations: $500, $100, $50, $10, $5, and $1

When a user withdraws an amount from the ATM, the machine tries to dispense the amount using the least number of bills possible.

For instance, if the user requests $1234, the ATM dispenses 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 4 bills of $1. On the other hand, if the user requests $1235, the machine dispenses 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 1 bill of $5

Use the skeleton code provided to create an ATM dispenser that takes the amount and prints the least number of bills that makes up the amount in the following format:

__ bills of $500 + __ bills of $100 + __ bills of $50 + __ bills of $10 + __ bills of $5 + __ bills of $1

Apply chain of responsibility pattern such that each denomination is handled by a separate handler.

Below is the code:

abstract class Handler

{

    Handler successor;

    abstract public String dispense(int amount);

}

class Handler500 extends Handler

{

}

class Handler100 extends Handler

{

}

class Handler50 extends Handler

{

}

class Handler10 extends Handler

{

}

class Handler5 extends Handler

{

}

class Handler1 extends Handler

{

}

class ATM

{

    Handler handler;

    public ATM(Handler handler)

    {

        this.handler = handler;

    }

    public string dispense(int amount)

    {

        return handler.dispense();

    }

}

public class ATMTester

{

    public static void main(String[] args)

    {

                    ATM atm;

                /// TODO - create an ATM object with the appropriate handlers and store it in the variable "atm"

System.out.println(atm.dispense(1234)); // should display: 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 4 bills of $1

System.out.println(atm.dispense(1235)); // should display: 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 1 bills of $5

    }

}

Answer 1

Please find the answer below.
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ATMTester.java

package c15;
abstract class Handler

{

   Handler successor;

   abstract public String dispense(int amount);

}

class Handler500 extends Handler

{

   @Override
   public String dispense(int amount) {
       //successor of the 500 handle will be 100
       successor = new Handler100();
      
       //get number of 500
       int count = amount/500;
      
       //get remaining amount
       amount = amount%500;
      
       //print count
       if(count!=0)
           return count+" bills of $500 + "+successor.dispense(amount);
       else
           return successor.dispense(amount);
   }

}

class Handler100 extends Handler

{

   @Override
   public String dispense(int amount) {
       successor = new Handler50();
       int count = amount/100;
       amount = amount%100;
       if(count!=0)
           return count+" bills of $100 + "+successor.dispense(amount);
       else
           return successor.dispense(amount);
   }}

class Handler50 extends Handler

{

   @Override
   public String dispense(int amount) {
       successor = new Handler10();
       int count = amount/50;
       amount = amount%50;
       if(count!=0)
           return count+" bills of $50 + "+successor.dispense(amount);
       else
           return successor.dispense(amount);
   }
}

class Handler10 extends Handler

{
   @Override
   public String dispense(int amount) {
       successor = new Handler5();
       int count = amount/10;
       amount = amount%10;
       if(count!=0)
           return count+" bills of $10 + "+successor.dispense(amount);
       else
           return successor.dispense(amount);
   }
}

class Handler5 extends Handler

{
   @Override
   public String dispense(int amount) {
       successor = new Handler1();
       int count = amount/5;
       amount = amount%5;
       if(count!=0)
           return count+" bills of $5 "+successor.dispense(amount);
       else
           return successor.dispense(amount);
   }
}

class Handler1 extends Handler

{
   @Override
   public String dispense(int amount) {
       //handle 1 will not have any successor
       if(amount!=0)
           return amount+" + bills of $1 ";
       else
           return "";
   }
}

class ATM

{

   Handler handler;

   public ATM(Handler handler)

   {

       this.handler = handler;

   }

   public String dispense(int amount)

   {

       return handler.dispense(amount);

   }

}

public class ATMTester

{

   public static void main(String[] args)

   {

       //create atm object
       ATM atm;

       //create an ATM object with the appropriate handlers and store it in the variable "atm"
       //500 handle will be the first one
       Handler handle500 = new Handler500();
       atm = new ATM(handle500);

       System.out.println(atm.dispense(1234)); // should display: 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 4 bills of $1

       System.out.println(atm.dispense(1235)); // should display: 2 bills of $500 + 2 bills of $100 + 3 bills of $10 + 1 bills of $5

   }

}

output