四则运算

//这个代码吧 略有缺陷 四则运算的乘除与加减 只能从左到右依次计算 还没想好怎么做
import java.util.Random;
import java.util.Scanner;

public class test {
    public static void main(String[] args) {
        String []cun =new String[10000];
        double []daan =new double [1000];
        double [ ]shuru = new double [1000];
        String []cuotiji = new String[1000];
        double []cuotidaan = new double[1000];
        int  zhengquegeshu=0;
        int cuogeshu=0;
        double zhengquelv;
        String[] cunfuhao = new String[10000];
        Random random = new Random();
        int cout=0;//记个数
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入需要的题目数量：");
        int n = sc.nextInt();
        System.out.println("请输入操作数的个数");
        int m = sc.nextInt();
        System.out.println("请输入取值范围");
        int max = sc.nextInt();
        int min = sc.nextInt();
        for (int i = 0; i < n; i++) {//出题个数
            char a ='+';
            int j;
            for (j = 0; j < m; j++) {//操作数的个数
                double s = shuzi(max, min);
                if(j==0){
                    daan[i]= s;
                }
                else {
                    switch (a){
                        case '+':{
                            daan[i]+=s;
                            break;
                        }
                        case '-':{
                            daan[i]-=s;
                            break;
                        }
                        case '*':{
                            daan[i]*=s;
                            break;
                        }
                        case '/':{
                            daan[i]/=s;
                        }
                        default:break;
                    }
                }
                if (j == m - 1) {
                    System.out.println("=");
                     a = '=';
                }
                else {
                    a = caozuofu();
                }




                if(j==0) {
                    cun[i] = "" + s + a;
                    cout++;
                }
                else{
                    cun[i] += "" + s + a;
                    cout++;
                }//存储完毕
            }
            System.out.println("请输入你的答案");
            shuru[i]= sc.nextDouble();
            //cheak(cun,x,cout);//查重
        }
        for (int i = 0; i < n; i++) {
            if(shuru[i]==daan[i]){
                zhengquegeshu++;
            }
            else {
                cuotiji[cuogeshu]= cun [i];
                cuotidaan[cuogeshu]= daan[i];
                cuogeshu++;
            }
        }
        zhengquelv = zhengquegeshu*1.00 / n*100;
        System.out.println("您的正确率为"+zhengquelv+"%");
        System.out.println("您的错题有：");
        for (int i = 0; i < cuogeshu; i++) {
            System.out.println(cuotiji[i]);
        }
        System.out.println("是否重做错题 1.是 2.否");
        int panduan= sc.nextInt();
        if(panduan == 1){
            for (int i = 0; i < cuogeshu; i++) {
                System.out.println(cuotiji[i]);
                double key = sc.nextDouble();
                if(key ==cuotidaan[i]){
                    System.out.println("做对了");
                }
                else{
                    System.out.println("又做错了");
                }
            }
        }
    }
    public  static  double shuzi(int max ,int min){//生成四则运算的数字
        Random random = new Random();
        double  number = random.nextInt(max-min) + min;
        System.out.print(number);
        return number;
    }
    public static  char caozuofu(){//生成操作符
        Random random = new Random();
        char a='0' ;
        int mark = random.nextInt(4);
        switch (mark) {
            case 0: {
                System.out.print("+");
                a='+';
                break;
            }
            case 1: {
                System.out.print("-");
                a='-';
                break;
            }
            case 2: {
                System.out.print("*");
                a='*';
                break;
            }
            case 3: {
                System.out.print("/");
                a='/';
                break;
            }
        }
        return a;
    }
    /*public  static  void cheak(String [][]cun, String []x,int cout){
            int flag = 0;
           if(cout==0){
            System.out.println("错误");
        }
        for (int i = 0; i < cout; i++) {
            if(x.equals(cun[i])){
               flag =1;
            }
        }
        if(flag==0) {
            System.out.println("重复");
        }
    }*/

}