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public class Item implements Comparable
{
    private String name, category;
    private int quantity;
    private double price;

    public Item(String nam,String cate,int quant,double pric)
    {
        name = nam;
        category = cate;
        quantity = quant;
        price = pric;
    }

    public String toString()
    {
        return name + ", " + category + ", " + quantity + ", " + price;
    }

    public boolean equals(Object other)
{
    if (price == ((Item)other).getPrice())
    return true;
    else
    return false;
}


    public String getName()
    {
        return name;
    }

    public String getCategory()
    {
        return category;
    }

    public int getQuantity()
    {
        return quantity;
    }

    public double getPrice()
    {
        return price;
    }

    public int compareTo(Object other)
    {
        int result;

        String otherPrice = ((Item)other).getPrice(); 
        String otherCategory = ((Item)other).getCategory();

        if (price.equals(otherPrice)) //Problem Here
            result = category.compareTo(otherCategory);
        else
            result = price.compareTo(otherPrice);
        return result;
    }
}

-------------------------------

at points //problem here. I get the compile error saying that doubles cannot be dereferenced. I understand that doubles are of primitive type, but I still don't fully understand how to use them in a compareTo method. So after overriding the equals method, how do I use it in the compareTo method? I want to first compare price. If price equals otherPrice, category must be compared next.

Matt
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  • Please use a language tag to specify language – horns Feb 16 '15 at 21:16
  • 2
    Dealing with primitives in methods such as `compareTo` and `equals` requires the use of their object-based counterparts (such as `Double` for doubles). You can autobox/unbox primitives to/from their object types automatically. Use care when comparing doubles... since "equality" is generally very hard to achieve by simply using "==". – Ryan J Feb 16 '15 at 21:20
  • Also, boo for comparing doubles with `equals` (or `==`), and using them for currency. – vanza Feb 16 '15 at 21:52
  • possible duplicate of [Char cannot be dereferenced? using compareTo](http://stackoverflow.com/questions/13277808/char-cannot-be-dereferenced-using-compareto) –  Feb 16 '15 at 21:56

1 Answers1

-1

equals() as defined compares the price of items, so the line should read:

if (this.equals(other))
Walter Misar
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