Printing distinct integers in an array

Question

I\'m trying to write a small program that prints out distinct numbers in an array. For example if a user enters 1,1,3,5,7,4,3 the program will only print out 1,3,5,7,4.

Answer 1

What you want can be accomplished using Java collection API, but not exactly as an one-liner, due to fact collection methods work with Objects and not primitives. J2SE lacks methods that convert, say, int[] to Integer[], but Apache Commons Lang library contains such useful methods, like ArrayUtils.toObject() and ArrayUtils.toPrimitive().

Using them, method to remove duplicated elements from an integer array looks something like this:

public static int[] removeDuplicates(int... array) {
    Integer[] ints = ArrayUtils.toObject(array);
    Set set = new LinkedHashSet(Arrays.asList(ints));
    return ArrayUtils.toPrimitive(set.toArray(new Integer[set.size()]));
}

If your application is likely to include more of array/collection manipulation, I suggest you take a look at that library, instead of implementing things from scratch. But, if you're doing it for learning purposes, code away!