Question

I have an array:

int num[] = {10, 20, 30, 40, 50};

I get current minute from Calendar and compare it with array above to get exactly element in array.

My code as following, after compare it often get first element, it’s not correct as my wish, pls help to correct me. Thanks

public static int getMinute(int no) {
    int num[] = {10, 20, 30, 40, 50};
    for (int i = 0; i < num.length;; i++) {
        if (no >= num[i]) {
            no = num[i];
            break;
        }
    }
    return no;
}

Answer 1

Here are two solutions (both working in the 0..59 range):

1. If your array is really 0, 10, 20, ..., 50 you could just do:

   return 10 * (no / 10);
   

2. If you have more a more complex matching you could use a TreeSet like this:

   TreeSet<Integer> c = new TreeSet<Integer>(Arrays.asList(0, 4, 23, 12, 41));
   
   System.out.println(c.lower(5));   // return 4
   System.out.println(c.lower(54));  // return 41
   System.out.println(c.lower(32));  // return 23
   

   Just note that you would need to include a lower bound to get it to work, otherwise TreeSet.lower might return null.