1 import java.util.Scanner;
2
3 /**
4 * 功能：用位运算，实现乘法运算，但仅限于乘数是偶数。
5 */
6 public class Main2 {
7
8 public int powerN(int m, int n) {
9 while (n > 0) {
10 m = m << 1;
11 n--;
12 }
13 return m;
14 }
15
16 public static void main(String[] args) {
17
18 Main2 main2 = new Main2();
19 Scanner scanner = new Scanner(System.in);
20
21 int input = 0;
22 int n = 0;
23
24 while (scanner.hasNext()) {
25 input = scanner.nextInt();
26
27 if (input == 0 || input % 2 == 1) {
28 System.out.println("the intput value is invalid!");
29 continue;
30 }
31
32 n = 0;
33
34 while (input != 1) {
35 n++;
36 input = input / 2;
37 }
38
39 System.out.println(main2.powerN(2, n));
40 }
41 }
42 }
