1 package demo;
2
3 import java.text.DecimalFormat;
4 import java.util.Random;
5
6 public class Demo {
7
8 public static void main(String[] args) {
9 maths();
10 }
11
12 public static void maths() {
13 Random number = new Random();
14 for (int x = 1; x <= 300; x++) {
15 int compute = number.nextInt(4);
16 int a = number.nextInt(100);
17 int b = number.nextInt(100);
18 switch (compute) {
19 case 0:
20 System.out.println("第" + x + "条:");
21 System.out.println(a + "+" + b + "=" + (a + b));
22 break;
23 case 1:
24 System.out.println("第" + x + "条:");
25 System.out.println(a + "-" + b + "=" + (a - b));
26 break;
27 case 2:
28 System.out.println("第" + x + "条:");
29 System.out.println(a + "×" + b + "=" + (a * b));
30 break;
31 case 3:
32 if (b == 0) {
33 x--;
34 break;
35 } else {
36 if (a % b == 0) {
37 System.out.println("第" + x + "条:");
38 System.out.println(a + "÷" + b + "=" + (a / b));
39 } else {
40 System.out.println("第" + x + "个:");
41 double c = (double) a / b;
42 String y = new DecimalFormat("0.00").format(c);
43 System.out.println(a + "÷" + b + "=" + y);
44 }
45 }
46 break;
47 default:
48 break;
49 }
50 }
51 }
52 }
![](https://images2015.cnblogs.com/blog/1118762/201703/1118762-20170310230918889-610435197.png)
![](https://images2015.cnblogs.com/blog/1118762/201703/1118762-20170310230933967-958891499.png)