编写一个Java考试小程序出错

import java.util.Arrays;
import java.util.Scanner;
class Question{
    String text;
    String []options;
    Question(){}
    Question(String text,String []options){
        this.text=text;
        this.options=options;
    }
     boolean check(char []answers){
         return false;}
     void print() {}
}
class  MultiChoice extends Question{
    char[]answers;
    char[]answer;
    MultiChoice(){}
    MultiChoice(String text,String []options,char []answer){
        this.text=text;
        this.options=options;
        this.answer=answer;
        System.out.println(text);
        System.out.println(Arrays.toString(options));
    }
    boolean check(char []answers) {
        if(answers.length<answer.length||answers.length>answer.length)
        System.out.println("还得努力呀！");
        else {
    int []rest;
    rest=new int[answer.length];
    for(int i=0;i<answer.length;i++)
    {rest[i]=Arrays.binarySearch(answers, answer[i]);
    if (rest[i]<0)
    {    System.out.println("还得努力呀！");
        break;}
    else if(rest[answer.length]>0)
        System.out.println("恭喜，答对了！");
    }
        }
         return true;    
    }
}
class SingleChoice extends Question{
    char answer;
    char []answers;
    SingleChoice(){}
    SingleChoice(String text,String []options,char answer){
        this.text=text;
        this.options=options;
        this.answer=answer;
        System.out.println(text);
        System.out.println(Arrays.toString(options));
    }
    boolean check(char[] answers) {
        this.answers=answers;
        return answers[0]==answer;
            
    }
    void print() {
        if(answers.length>1||answers.length==0) 
            System.out.println("还得努力呀！");
        else if(answer==answers[0])
            System.out.println("恭喜，答对了！");
        else
            System.out.println("还得努力呀！");    
        }
    }
public class Test {
    public static void main(String args[]) {
      MultiChoice A=new MultiChoice("三国演义中的三绝是谁？",new String[]{"A.曹操","B.刘备","C.关羽","D.诸葛亮"},new char[]{'A','C','D'});    
      System.out.print("请选择：");
      Scanner sc=new Scanner(System.in);
    String x=sc.next();
    char []z;
    z=new char[x.length()];
    for(int i=0;i<x.length();i++)
     {z[i]=x.charAt(i);
    Character.toUpperCase(z[i]);}
    A.check(z);
     SingleChoice B=new SingleChoice("最早向刘备推荐诸葛亮的是谁？",new String[]{"A.徐庶","B.司马徽","C.鲁肃","D.关羽"},'A');    
     System.out.print("请选择：");
     String y=sc.next();
     char []g;
        g=new char[y.length()];
        for(int i=0;i<y.length();i++)
         {z[i]=y.charAt(i);
        Character.toUpperCase(g[i]);}
    B.check(g);
    B.print();
    sc.close();
    }
    }

import java.util.Arrays;

import java.util.Locale;
import java.util.Scanner;

abstract class Question{
    private final String text;
    private final String []options;

    public Question(String text,String []options){
        this.text=text;
        this.options=options;
    }

    public String getText(){
        return this.text;
    }

    public String[] getOptions(){
        return this.options;
    }

    abstract void check(char []answers);
}

class MultiChoice extends Question{

    private final char[] answer;

    MultiChoice(String text,String []options,char []answer){
        super(text,options);
        this.answer=answer;
        System.out.println(text);
        System.out.println(Arrays.toString(options));
    }

    public void check(char[] answers) {
        if (answers.length < answer.length || answers.length > answer.length)
            System.out.println("还得努力呀！");
        else {
            Arrays.sort(answer);
            String answerStr = String.valueOf(answer);
            Arrays.sort(answers);
            String answersStr = String.valueOf(answers);
            if(answerStr.equals(answersStr)){
                System.out.println("恭喜，答对了！");
            } else{
                System.out.println("还得努力呀！");
            }
        }
    }

}

class SingleChoice extends Question{

    char answer;

    SingleChoice(String text,String []options,char answer){
        super(text,options);
        this.answer=answer;
        System.out.println(text);
        System.out.println(Arrays.toString(options));
    }

    public void  check(char[] answers) {
        if(answers.length != 1)
            System.out.println("还得努力呀！");
        else if(answer==answers[0])
            System.out.println("恭喜，答对了！");
        else
            System.out.println("还得努力呀！");
    }

}

public class Test {
    public static void main(String args[]) {

        MultiChoice A=new MultiChoice("三国演义中的三绝是谁？",new String[]{"A.曹操","B.刘备","C.关羽","D.诸葛亮"},new char[]{'A','C','D'});
        System.out.print("请选择：");
        Scanner sc=new Scanner(System.in);
        String x=sc.next();
        A.check(x.toUpperCase(Locale.ROOT).toCharArray());

        SingleChoice B=new SingleChoice("最早向刘备推荐诸葛亮的是谁？",new String[]{"A.徐庶","B.司马徽","C.鲁肃","D.关羽"},'A');
        System.out.print("请选择：");
        String y=sc.next();
        B.check(y.toUpperCase(Locale.ROOT).toCharArray());
        sc.close();
    }
}

1.从编程思维看，建议在基础知识上多巩固，尽快形成学习体系
2.从代码逻辑看，还停留在顺序编程阶段，建议尽快适应面向对象，可以让思路更清晰，代码更简洁
3.最好不要省略代码，比如if后的大括号，阅读体验不好，并不会让人觉得很酷

问题：
{z[i]=y.charAt(i); 第87行，你直接复制过来的时候没有改数组，应该是{g[i]=y.charAt(i);