9.11

今天讲了，用愚公移山的例子对我们讲了，面对程序，我们要复杂问题简单化，简单问题流程化，具体分为四个步骤：分解、模、抽象和算法，还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：

package ceshi;
import java.util.Random;

import java.util.Scanner;


public class sizeyunxuan {

    public static void operate() {
        String[]operate=new String[]{"+","-","*","/"};
        Random r=new Random();
        System.out.print(operate[r.nextInt(4)]);
    }
    public static void main(String[] args) {

        int []a=new int[100];
        int []b=new int[100];


        Scanner scan =new Scanner(System.in);
        int n;
        System.out.println("请输入需要的题目数：");
        n=scan.nextInt();



        int i,j;
        for(i=0;i<n;i++)
        {

            Random r=new Random();
            a[i]=r.nextInt(99);
            b[i]=r.nextInt(9);

            for(j=0;j<i;j++) {
                if(a[i]==b[j]&&b[i]==a[j]) {
                    a[i]=r.nextInt(99)-1;
                }
            }
            int t=(int)r.nextInt(4);
            switch(t)
            {
                case 0:
                    System.out.println(a[i]+" + "+b[i]+"=");
                    break;
                case 1:
                    System.out.println(a[i]+" - "+b[i]+"=");
                    break;
                case 2:
                    System.out.println(a[i]+" * "+b[i]+"=");
                    break;
                case 3:
                    System.out.println(a[i]+" / "+b[i]+"=");
                    break;
            }




        }

    }

}