BinarySearch.java

package com.company;

public class BinarySearch {

    public static void main(String[] args) {
        int[] arr = {-15,-10,0,3,5,6,8,10};
        int target = 6;
        int ans = binarySearch(arr,target);
        System.out.println(ans);
    }

    //return the index
    //return -1 if it does not exist
    static int binarySearch(int[] arr, int target) {
        int start = 0;
        int end = arr.length -1;

        while (start <= end) {
            //find the middle element
            //int mid = (start + end) / 2;
            //the below is a better mid value finder
            int mid = start + (end - start) / 2;

            if (target < arr[mid]) {
                end = mid - 1;
            } else if (target > arr[mid]) {
                start = mid + 1;
            } else {
                //answer found
                return mid;
            }
        }
        return -1;
    }
}