Mooc fi. Part 5 Part4 Adding Money

[tangara goh]

I managed to get someone to send me the Part 5 exercises but without the TCMBeans I can't tell what is wrong cos I am using Eclipse.

I hope someone can tell me how to overcome the error in this case:

The requirements as follows :
Let's create a method for the terminal that can be used to add money to a payment card. Recall that the payment that is received when adding money to the card is stored in the register. The basis for the method:

public class PaymentTerminal {
		
	private double money;  // amount of cash
	    private int affordableMeals; // number of sold affordable meals
	    private int heartyMeals;  // number of sold hearty meals
	    private double change;
	    private double cardBalance;
	    
	    public PaymentTerminal() {
	        // register initially has 1000 euros of money
	    	money = 1000.00;
	    }
	    
	    //Part II : Payment Terminal And Cash
	   // public double eatAffordably(double payment) {
	        // an affordable meal costs 2.50 euros
	        // increase the amount of cash by the price of an affordable meal and return the change
	        // if the payment parameter is not large enough, no meal is sold and the method should 
	    	//return the whole payment
	    	//money = money + 2.50;
	    	//change = payment - 2.50;
	    	//if (payment < 2.50) {
	    		//return payment; 
	    		//}
	    	//else {
	    	//	affordableMeals++;
	    	//	return change;
	    	//}
	    	
	  //  }

	   // public double eatHeartily(double payment) {
	      //   a hearty meal costs 4.30 euros
	      //   increase the amount of cash by the price of a hearty meal and return the change
	      //   if the payment parameter is not large enough, no meal is sold and the method should 
	    //	return the whole payment
	    	//money = money + 4.30;
	    	//change = payment - 4.30;
	    	//if (payment < 4.30) {
	    		//return payment; 
	    		 	//	}
	    	//else {
	    		//heartyMeals++;
	    		//return change;
	    	//}}
	    	
	    	// Part III : Card Payment
	    	public boolean eatAffordably(PaymentCard card) {
	            // an affordable meal costs 2.50 euros
	            // if the payment card has enough money, the balance of the card is decreased by the price, and the method returns true
	            // otherwise false is returned
	    	if(card.balance() > 2.50) {
	    		affordableMeals++;
	    		//money = money + 2.50;
	    		cardBalance = card.balance() - 2.50;
	    		money = money - 2.50;
	    		return true;
	    	}
	    		return false;
	        }

	    	
	        public boolean eatHeartily(PaymentCard card) {
	            // a hearty meal costs 4.30 euros
	            // if the payment card has enough money, the balance of the card is decreased by the price, and the method returns true
	            // otherwise false is returned
	        if(cardBalance > 4.30 ) {
	        	heartyMeals++;	        
	        	//money = money + 4.30;
	        	cardBalance = cardBalance - 4.30;	        	
	        	money = money - 4.30;
	        	return true;
	        }	    
	        	return false;
	    }
	        // Part 4 : Let's create a method for the terminal that can be used to add money to a payment card. 
	        //Recall that the payment that is received 
	        //when adding money to the card is stored in the register. The basis for the method:
	        
	        public void addMoneyToCard(PaymentCard card, double sum) {
	            // ...
	        	money = 1000;
	        	money = money + sum;
	        }
	        
	        

	    public String toString() {
	        return "money: " + money + ", number of sold afforable meals: " + affordableMeals + ", number of sold hearty meals: " + heartyMeals;
	    }
	    
	    //public class Main {

	     
	            // write experimental main programs here

	      //  public static void main(String[] args) {
	        //    PaymentTerminal unicafeExactum = new PaymentTerminal();
	            // Part 3
	           // double change = unicafeExactum.eatAffordably(10);
	           // System.out.println("remaining change: " + change);

	          //  PaymentCard annesCard = new PaymentCard(7);

	            //boolean wasSuccessful = unicafeExactum.eatHeartily(annesCard);
	            //System.out.println("there was enough money: " + wasSuccessful);
	            //wasSuccessful = unicafeExactum.eatHeartily(annesCard);
	            //System.out.println("there was enough money: " + wasSuccessful);
	            //wasSuccessful = unicafeExactum.eatAffordably(annesCard);
	            //System.out.println("there was enough money: " + wasSuccessful);

	            //System.out.println(unicafeExactum); 


	            /* Part 2 
	            double change = unicafeExactum.eatAffordably(10);
	            System.out.println("remaining change " + change);

	            change = unicafeExactum.eatAffordably(5);
	            System.out.println("remaining change " + change);

	            change = unicafeExactum.eatHeartily(4.3);
	            System.out.println("remaining change " + change);

	            System.out.println(unicafeExactum);
	             */
	            
	            
	            //public class MainProgram {
	        //Part 4      
	    	public static void main(String[] args) {
	                    PaymentTerminal unicafeExactum = new PaymentTerminal();
	                    System.out.println(unicafeExactum);

	                    PaymentCard annesCard = new PaymentCard(2);

	                    System.out.println("amount of money on the card is " + annesCard.balance() + " euros");

	                    boolean wasSuccessful = unicafeExactum.eatHeartily(annesCard);
	                    System.out.println("there was enough money: " + wasSuccessful);

	                    unicafeExactum.addMoneyToCard(annesCard, 100);

	                    wasSuccessful = unicafeExactum.eatHeartily(annesCard);
	                    System.out.println("there was enough money: " + wasSuccessful);

	                    System.out.println("amount of money on the card is " + annesCard.balance() + " euros");

	                    System.out.println(unicafeExactum);
	                }
	           // }
	        }
/*	  
money: 1000.0, number of sold afforable meals: 0, number of sold hearty meals: 0
amount of money on the card is 2.0 euros
there was enough money: false
there was enough money: true
amount of money on the card is 97.7 euros
money: 1100.0, number of sold afforable meals: 0, number of sold hearty meals: 1*/
	

public class PaymentCard {
	private double balance;

    public PaymentCard(double balance) {
        this.balance = balance;
    }

    public double balance() {
        return this.balance;
    }

    public void addMoney(double increase) {
        this.balance = this.balance + increase;
    }
   
    // Part 1 : Dumb payment card
    public boolean takeMoney(double amount) {
        // implement the method so that it only takes money from the card if
        // the balance is at least the amount parameter.
        // returns true if successful and false otherwise
    if(balance >= amount) {
    balance = balance - amount;
    return true;
    }
    return false;
    }

    
  //  public class MainProgram {
        public static void main(String[] args) {
            PaymentCard petesCard = new PaymentCard(10);

            System.out.println("money " + petesCard.balance());
            boolean wasSuccessful = petesCard.takeMoney(8);
            System.out.println("successfully withdrew: " + wasSuccessful);
            System.out.println("money " + petesCard.balance());

            wasSuccessful = petesCard.takeMoney(4);
            System.out.println("successfully withdrew: " + wasSuccessful);
            System.out.println("money " + petesCard.balance());
        }
    }

My question is at the Main Program public static void main(String[]args) there is this line new PaymentCard(10) but eclipse is saying that

 //    PaymentTerminal unicafeExactum = new PaymentTerminal();
	            // Part 3
	           // double change = unicafeExactum.eatAffordably(10);

eatAffordably is int but the method contains a reference object PaymentCard so is there anything wrong with the program or how should I overcome the error ?

Thanks.

[Carey Brown]

public boolean eatAffordably(PaymentCard card) {

The method says that it is expecting a PaymentCard as an argument, not an int.

[tangara goh]

Carey Brown wrote:

public boolean eatAffordably(PaymentCard card) {

The method says that it is expecting a PaymentCard as an argument, not an int.

But, at the public void main(String [] args) it has 10 inside the eatAffordably method...is that a mistake then ?
unicafeExactum.eatAffordably(10);

[Carey Brown]

Well, one or the other is a mistake. Seeing as how you have a Card class I'm going to guess that the '10' is the mistake.

There's something not quite right with your Terminal class, it is maintaining a cardBalance. That should be the job of the Card class not the Terminal class.

          public boolean eatAffordably(PaymentCard card) {
                // an affordable meal costs 2.50 euros
                // if the payment card has enough money, the balance of the card is decreased by the price, and the method returns true
                // otherwise false is returned
          if(card.balance() > 2.50) {
              affordableMeals++;
              //money = money + 2.50;
              cardBalance = card.balance() - 2.50;
              money = money - 2.50;
              return true;
          }
              return false;
            }

This code is not defining which class is responsible for what very clearly. Who is supposed to handle card balance? Why does Terminal even have 'money'? The test for balance compared to 2.50 is already in the Card class (see takeMoney()) but you're not using it.

[tangara goh]

Carey Brown wrote:Well, one or the other is a mistake. Seeing as how you have a Card class I'm going to guess that the '10' is the mistake.

This code is not defining which class is responsible for what very clearly. Who is supposed to handle card balance? Why does Terminal even have 'money'? The test for balance compared to 2.50 is already in the Card class (see takeMoney()) but you're not using it.

Thanks Carey.

The CardBalance is my mistake.  It is not there in the template code but I was trying to solve the previous part I, II and III and probably my method is wrong, even though the answer can be derived.
But, now with part IV, I can see that it is a real problem cos now I can't get the answer now.

[Campbell Ritchie]

Is using doubles for money also in the template code? That is another mistake.