小學四則運算

 1 import java.util.Random;
 2 import java.util.Scanner;
 3 
 4 
 5 
 6 
 7 public class test {
 8 public static void main(String[]args){
 9 int n;
10 Scanner in=new Scanner(System.in);
11 do{
12 do{
13 System.out.println("你要进行多少位数的四则运算？");
14 n=in.nextInt();
15 }while(n<1);
16 int x=new Random().nextInt((int) Math.pow(10, n)) + 1;
17 int y=new Random().nextInt((int) Math.pow(10, n)) + 1;
18 int o=new Random().nextInt(3);
19 float z=0;
20 float input;
21 String c="?";
22 boolean bigger=x>y?true:false;//小学生不会出现负数啊
23 switch(o)
24 {
25 case 0:
26 c="+";
27 z=x+y;
28 break;
29 case 1:
30 c="-";
31 if(bigger)
32 z=x-y;
33 else 
34 z=y-x;
35 break;
36 case 2:
37 c="*";
38 z=x*y;
39 break;
40 case 3:
41 c="/";
42 z=(float)x/y;
43 break;
44 default:
45 System.out.println("error!");
46 }
47 do{
48 if(bigger)
49 System.out.print(x + c + y+"=");
50 else System.out.print(y + c + x+"=");
51 input=in.nextFloat();
52 if(input!=z)
53 System.out.println("算错了!");
54 }while(input!=z);
55 }while(true);
56 }
57 }