java - 使用 while 循环返回开始

Question

/--------------------------------------------------Quizzes.java----------------------------------------------------/ 导入 java.util.Scanner； 导入 java.text.NumberFormat;

公开课测验 { public static void main(String[] args) {

     Scanner scan = new Scanner(System.in);
        NumberFormat per = NumberFormat.getPercentInstance();     


  //User to input keys for quiz
     System.out.println("How many questions are in the quiz?");
     int numques = scan.nextInt();
     int[] keys = new int[numques];

     for (int i=0; i<keys.length; i++)
     {
        System.out.print("Please enter the key for # " + (i+1)+ ": " );
        keys[i] = scan.nextInt();         
     }

  //User to input answer
     System.out.println("\nGrading Quizzes");
     System.out.println("--------------------");

        int correct=0;

     for (int i=0; i<keys.length; i++)
     {
        System.out.println("Please enter the answer for # " + (i+1)+ ":  ");
        int answer= scan.nextInt();
            if (answer== keys [i])
            {
                System.out.print("Number "+(i+1)+" is correct.\n");
                correct++;
            }
            else 
            {
                System.out.print("Number "+(i+1)+" is incorrect.\n");

            }
     }
    double cal=(double) correct/numques;
        System.out.println("Total number of correct is "+correct);
     System.out.println("The percent correct is " +per.format(cal));

        System.out.println("Would you like to grade another quiz? (y/n)");
        String user_input=scan.next();

        while(user_input.equals("y"))
        {   correct=0;
     for (int i=0; i<keys.length; i++)
     {
        System.out.println("Please enter the answer for # " + (i+1)+ ":  ");
        int answer= scan.nextInt();
            if (answer== keys [i])
            {
                System.out.print("Number "+(i+1)+" is correct.\n");
                correct++;
            }
            else {
            System.out.print("Number "+(i+1)+" is incorrect.\n");   }

            } 
           cal=(double) correct/numques;
           System.out.println("Total number of correct is "+correct);
        System.out.println("The percent correct is " +per.format(cal));
      }
           System.out.println("Goodbye!");

 }

如何让程序返回到用户必须使用 while 循环输入答案的位置？无论我尝试什么，当它打印出来时，“你想给另一个测验打分吗，如果用户输入 y，它就会结束。任何人都可以指出我做错了什么

编辑 1:好吧，我让它在 while 循环后再次运行，但它一直要求我一遍又一遍地输入问题的答案，它没有跳出循环，它没有回到它询问我是否要给另一个评分的部分。这是输出

测验有多少道题？2个请输入#1 的 key :1请输入#2 的 key :2

评分测验

请输入#1的答案:
1个1号是正确的。请输入#2 的答案:
3个数字 2 不正确。正确总数为1正确率是 50%你想给另一个测验评分吗？ (是/否)是请输入#1 的答案:
1个1号是正确的。请输入#2 的答案:
2个2号是正确的。正确总数为2正确率是 100%请输入#1 的答案:
1个1号是正确的。请输入#2 的答案:
2个2号是正确的。正确总数为2正确率是 100%请输入#1 的答案:

Answer 1

while(user_input.equals('y'))

应该是

while(user_input.equals("y")) // see the double quotes here

您的代码存在问题，字符“y”被自动装箱为 Character 类的实例，该类是 Object 的子类.

Class Object is the root of the class hierarchy. Every class has Object as a superclass. All objects, including arrays, implement the methods of this class

public boolean equals(Object) 的候选项也是如此。

boolean equals(Object) 的

String 实现检查实例是否为String 类型。如果失败，它将简单地返回 false。如果您想与 'y' 进行比较，请试试这个。

while(user_input.equals(((Character)'y').toString()))