1.面对程序，我们要复杂问题简单化，简单问题流程化;
2.具体分为四个步骤：分解、模、抽象和算法;
3.给我们讲了一些基础的语法,变量间的类型转换，数据类型转换方法，两种类型的变量
课堂测试:
1 package ceshi;
2 import java.util.Random;
3
4 import java.util.Scanner;
5
6
7 public class sizeyunxuan {
8
9 public static void operate() {
10 String[]operate=new String[]{"+","-","*","/"};
11 Random r=new Random();
12 System.out.print(operate[r.nextInt(4)]);
13 }
14 public static void main(String[] args) {
15
16 int []a=new int[100];
17 int []b=new int[100];
18
19
20 Scanner scan =new Scanner(System.in);
21 int n;
22 System.out.println("请输入需要的题目数：");
23 n=scan.nextInt();
24
25
26
27 int i,j;
28 for(i=0;i<n;i++)
29 {
30
31 Random r=new Random();
32 a[i]=r.nextInt(99);
33 b[i]=r.nextInt(9);
34
35 for(j=0;j<i;j++) {
36 if(a[i]==b[j]&&b[i]==a[j]) {
37 a[i]=r.nextInt(99)-1;
38 }
39 }
40 int t=(int)r.nextInt(4);
41 switch(t)
42 {
43 case 0:
44 System.out.println(a[i]+" + "+b[i]+"=");
45 break;
46 case 1:
47 System.out.println(a[i]+" - "+b[i]+"=");
48 break;
49 case 2:
50 System.out.println(a[i]+" * "+b[i]+"=");
51 break;
52 case 3:
53 System.out.println(a[i]+" / "+b[i]+"=");
54 break;
55 }
56
57
58
59
60 }
61
62 }
63
64 }