Trying to print the maximum value of the arraylist in java

Question

I've sorted my arraylist in descending order and now I want to print the max value. the arraylist contains a student's name and their grade. I want to print the name of the student with the highest grade. I don't need to print their grade. Just the name. this is my code

public void printStudent(){

    Collections.sort(studentList);
    Collections.reverse(studentList);
    System.out.println("Best student is: ");
    for (Student s: studentList){
        System.out.println(s.toString());
    }
}

Right now this prints the entire list of students and their grades however I just want to print the name of the student with the highest grade and I've tried many things but can't seem to get it to work. Thanks!

possible duplicate http://stackoverflow.com/questions/8304767/how-to-get-maximum-value-from-the-list-arraylist — , Nov 13 '13 at 14:50
Basically, your question needs to be reformulated as "How do I get the first item of an array list?", right? — BalusC, Nov 13 '13 at 14:51
Do you really need to sort *and* reverse to accomplish this? Is it too hard to just perform one pass with a loop? If you're lazy `Collections.max` is still better. You don't want to optimize prematurely, but I think this is a bit too much for this simple task. — Zong, Nov 13 '13 at 14:56

Stephen C · Answer 1 · 2013-11-13T15:02:07.643

5

Hint:

If you hare sorted a list into ascending order, where is the largest element?
If you then reverse the list, where is the largest element now?
How do you get the Nth element of a list? (Meta-hint ... read the javadoc!)

edited Nov 13 '13 at 15:02

answered Nov 13 '13 at 14:52

Stephen C

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This is the only answer that really helps OP to learn instead giving free code to just copy and paste to solve the homework... – Luiggi Mendoza Nov 13 '13 at 14:53

score 3 · Answer 2 · answered Nov 13 '13 at 14:52

3

Use Collections.max and not sorting.

answered Nov 13 '13 at 14:52

Lakatos Gyula

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This is the right approach in general, but the OP *may* have been instructed to sort and reverse the list ... – Stephen C Nov 13 '13 at 15:03
@ZongZhengLi - Why? This is clearly a beginners programming assignment designed to get the student started on the basics of programming. Expecting an "optimal" solution (in any sense) is beside the point for a student at this point in their learning. – Stephen C Nov 13 '13 at 15:22
@StephenC I agree, there's no need for perfection. But what do you think when a student can sort and reverse a list, but doesn't know how to access a particular element? I'd argue there are better ways to apply sorting and such in an educational context. – Zong Nov 13 '13 at 15:50

score 0 · Accepted Answer · answered Nov 13 '13 at 14:50

0

You already sorted the Customer in reverse order then the highest grade should be in the first position of your collection.

Do like below.

Customer c = customerList.get(0); // getting the first elementt
System.out.println(c.toString());

answered Nov 13 '13 at 14:50

Prabhakaran Ramaswamy

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score 0 · Answer 4 · answered Nov 13 '13 at 14:52

How is your Combarable interface setup? Collections.sort is based on this.

So either you can print customerList.get(customerList.size() - 1) to print the last index in your list. Or you can print customerList.get(0)

But as I said: This depends on how you compare Customer against each other.

Trying to print the maximum value of the arraylist in java

4 Answers4