1 import java.io.*;
2 import java.util.*;
3 public class J2_13 {
4 public static void main(String a[]) {
5 Scanner scanner = new Scanner(System.in); /*构造一个Scanner对象，其传入参数为System.in*/
6 System.out.println("Please enter a number to limit the random number that yout want:");
7 int k= scanner.nextInt(); /*读取一个int数值k */
8 int p= (int)(2+(k-2)*Math.random()) ;/*产生一个2-K之间的随机整数*/
9 if(yes(p))
10 System.out.println(p+" is prime。");
11 else
12 System.out.println(p+" is not prime。");
13 return;
14 }
15 /*判断一个数是否是素数*/
16 public static boolean yes(int q) {
17 boolean t=true;
18 for(int i=2;i<q;i++)
19 if(q%i==0) {
20 t=false;
21 break;
22 }
23 return t; /*返回boolean值*/
24 }
25 }