Java: Compare 3 numbers. Get the greatest of them

Question

I do have an ArrayList with numbers and I need to get the greatest of them. I thought this would actually solve the problem, but it doesn't for negative numbers since greatest equals 0... Any help?

    public static int greatest(ArrayList<Integer> list) {

    int greatest = 0;

    for (int k : list)
        greatest = Math.max(k, greatest);

    return greatest;

`return list.stream().max(Comparator.naturalOrder()).orElse(Integer.MIN_VALUE);` — Elliott Frisch, Sep 26 '17 at 15:59
You can initialize greatest with the first element of your list — bdanos, Sep 26 '17 at 15:59

RailTracer · Accepted Answer · 2017-09-26T21:24:47.027

3

One simple solution is to start with the first element from your list or collection. This has the extra benefit that is type independent.

Make sure you handle 0 size array regardless of how you decide to move forward.

edited Sep 26 '17 at 21:24

answered Sep 26 '17 at 16:01

RailTracer

88
6

score 0 · Answer 2 · answered Sep 26 '17 at 16:01

0

Get the first element of the list and make that the greatest.

int greatest = list.get(0);

answered Sep 26 '17 at 16:01

user2023608

470
5
18

score -1 · Answer 3 · answered Sep 26 '17 at 16:01

-1

You can initialize greatest to minimum value of an integer as:

int greatest = -2147483648;

answered Sep 26 '17 at 16:01

Ayush28

359
3
18

There's a constant [`Integer.MIN_VALUE`](https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html#MIN_VALUE) for this. You don't need to put magic numbers in the code. – khelwood Sep 27 '17 at 08:48

Java: Compare 3 numbers. Get the greatest of them

3 Answers3