import java.util.Arrays;import java.util.Random;public class Solution {    public void demo(int n) {        if (n < 2)            return;        int[] array = new int[n];        Random rand = new Random();        for (int i = 0; i < array.length; i++) {            array[i] = rand.nextInt(1000);        }        Arrays.sort(array);        int value =http://www.mamicode.com/ array[rand.nextInt(n)];        for (int i = 0; i < array.length; i++) {            value = array[i];            System.out.println("the number needs to be found:" + value);            System.out.println("the position of value is:"                    + binSearch(0, array.length - 1, value, array));            System.out.println("the position of value is:"                    + binSearch1(value, array));            System.out.println("the position of value is:"                    + binSearch2(0, array.length - 1, value, array));        }        System.out.println("**************");        for (int i = 0; i < array.length; i++) {            System.out.println(i + ":" + array[i]);        }        System.out.println("**************");    }    // 递归    public int binSearch(int low, int high, int value, int[] array) {        int mid = (low + high) / 2;        if (mid > 0 && mid < array.length - 1) {            if (array[mid] == value)                return mid;            else if (array[mid] < value) {                return binSearch(mid + 1, high, value, array);            } else {                return binSearch(low, mid - 1, value, array);            }        }        if (array[low] == value)            return low;        if (array[high] == value)            return high;        return -1;    }    // 非递归    public int binSearch1(int value, int[] array) {        int mid;        int low = 0;        int high = array.length - 1;        while (low <= high) {            mid = (low + high) / 2;            if (array[mid] == value) {                return mid;            } else if (array[mid] > value) {                high = mid - 1;            } else {                low = mid + 1;            }        }        return -1;    }    // 改进递归    public int binSearch2(int low, int high, int value, int[] array) {        if (low > high)            return -1;        int mid = low + (high - low) / 2;        if (array[mid] == value)            return mid;        else if (array[mid] < value) {            return binSearch2(mid + 1, high, value, array);        } else {            return binSearch2(low, mid - 1, value, array);        }    }    public static void main(String[] args) {        // TODO Auto-generated method stub        Solution s = new Solution();        s.demo(13);    }}