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Thread: finding the largest object help

  1. #1
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    Default finding the largest object help

    hi, i'm having trouble with this java programming problem. any help will be greatly appreciated



    Write a method that returns the largest object in an array of objects. The method signature is:

    public static Object max(Comparable[] a)

    all the objects are instances of the Comparable interface. The order of the objects in the array is determined using the compareTo method.

    Write a test program that create an array of ten strings, an array of ten integers, and an array of ten dates, and finds the largest string, integer, and date in the array.




    *i think the compareto method is what is confusing me*


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    Default Re: finding the largest object help

    Basically, the compareTo() method will return -1, 0 or 1. If the comparable object using this method is less than the comparable object in the parameters, it returns -1. If the comparable object using this method is equal to the comparable object in the parameters, it returns 0. If the comparable object using this method is greater than the comparable object in the parameters, it returns 1.

    So, lets say we wanted to compare two number (this is not actual code and will not compile):
    //Returns -1
    4.compareTo(5);
     
    //Returns 0
    4.compareTo(4);
     
    //Returns 1
    4.compareTo(3);

    Do you understand that much?
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    Super Moderator copeg's Avatar
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    Default Re: finding the largest object help

    Quote Originally Posted by aussiemcgr View Post
    Basically, the compareTo() method will return -1, 0 or 1.
    According to the Comparable API:
    "Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object. "

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    Default Re: finding the largest object help

    It doesn't have to be -1, 0, or 1. It just has to fall into one of these three categories: less than zero, equal to zero, or greater than zero.

    So using the compareTo() method, you're largest object compared to every other object will return a value greater than 0 (can you see why?)

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    Default Re: finding the largest object help

    Quote Originally Posted by helloworld922 View Post
    It doesn't have to be -1, 0, or 1. It just has to fall into one of these three categories: less than zero, equal to zero, or greater than zero.

    So using the compareTo() method, you're largest object compared to every other object will return a value greater than 0 (can you see why?)
    Ya, you got me there. I'm just used to working with tiny numbers and I overlooked that, but you are entirely correct.
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