Binary Search

public class Main {

    public static void main(String[] args) {

        public int binarySearch(int a[], int num) {

        if (num > a[a.length-1] || num < a[0]) {
        return -1;
        }

        int beginning = 0;
        int end = a.length-1;
        int middle = (beginning+end)/2;

        while (a[middle] != num) {
            if (num < middle) {
                end = middle;
            }
            else {
                beginning = middle;
            }
            middle = (beginning + end)/2;
        }
        return middle;
        }
    }
}