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我需要位于调查文件末尾的reportSummary()方法的帮助。我正在使用我在网上找到的说明从头开始构建一个调查计划。我一直到这一点,但我不确定我缺少什么。

当前错误(在使用下面的答案中使用帮助之后(:

C:UsersNaelDocumentsNetBeansProjectsSurveysrcsurveySurvey.java:156: error: illegal start of type
    if (questions[i] instanceof (DoubleQuestions))
C:UsersNaelDocumentsNetBeansProjectsSurveysrcsurveySurvey.java:156: error: not a statement
    if (questions[i] instanceof (DoubleQuestions))
C:UsersNaelDocumentsNetBeansProjectsSurveysrcsurveySurvey.java:156: error: ';' expected
    if (questions[i] instanceof (DoubleQuestions))
C:UsersNaelDocumentsNetBeansProjectsSurveysrcsurveySurvey.java:186: error: class, interface, or enum expected
}
4 errors
C:UsersNaelDocumentsNetBeansProjectsSurveynbprojectbuild-impl.xml:930: The following error occurred while executing this line:
C:UsersNaelDocumentsNetBeansProjectsSurveynbprojectbuild-impl.xml:270: Compile failed; see the compiler error output for details.

Survey.java:

    package survey;
import java.util.Scanner;
import java.io.Serializable;

public class Survey implements Serializable
{
    private String surveyName;
    private Question[] questions;
    private int numQuestions;
    private int maxResponses;
    private boolean initialized;
    public Survey(String n)
    {
        surveyName = n;
        initialized = false;
    }

        //initialize() sets up the numQuestions, MaxResponses, and questions for the survey
    public char Questions()
    {
        Scanner input = new Scanner(System.in);
        System.out.println("Initializing survey "" + surveyName + ""n");
        //add a method for password validation!?!?!?  yes!!!  see the bank accounts lab
        System.out.print("Enter max number of responses: ");
        maxResponses = input.nextInt();
        System.out.print("Enter number of questions: ");
        numQuestions = input.nextInt();
        input.nextLine(); //have to do this to "eat" the new line character or the next input won't work correctly
        System.out.println();
        questions = new Question[numQuestions];
           char choice='c';
        for(int i = 0; i < numQuestions;i++)
        {

        //output menu options
        System.out.println();      
        System.out.println("    S - Create a String Question");
        System.out.println("    N - Create a Integer Question");
        System.out.println("    D - Create a Double Question");

        //loop until a valid input is entered
            System.out.print("Enter choice: ");
            choice = input.next().charAt(0);
            input.nextLine(); //still have to "eat" the current response
            //if choice is one of the options, return it.  Otherwise keep looping
            if( choice == 'N'  )
            {
                 System.out.print("Enter text for question " + (i+1) + ": ");

            //you will also need to ask what KIND of question - right now, defaults to integer question
            questions[i] = new IntegerQuestion(input.nextLine(),maxResponses);
             initialized = true;
            }  
            else if(choice == 'S')
            {
                   System.out.print("Enter text for question " + (i+1) + ": ");
            //you will also need to ask what KIND of question - right now, defaults to integer question
            questions[i] = new TextQuestion(input.nextLine(),maxResponses);
             initialized = true;
            }
             else if(choice == 'D')
            {
                   System.out.print("Enter text for question " + (i+1) + ": ");
            //you will also need to ask what KIND of question - right now, defaults to integer question
            questions[i] = new DoubleQuestions(input.nextDouble(),maxResponses);
             initialized = true;
            }
            else
            {
                System.out.println("Invalid choice.  Ensure a capital letter. Please re-enter.");
                choice = '?';
            }
      }
                         return choice;
    }

    /*
        run() gives the survey to a new survey taker, basically asks all the questions in the survey
    */
    public void startSurvey()
    {
        if(initialized)
        {
            System.out.println("Welcome to the survey "" + surveyName + ""n");
            for(int i = 0;i < numQuestions; i ++)
            {
                questions[i].askQuestion();
            }
            System.out.println("Thank you for participating!");
        }
        else
        {
            System.out.println("Survey has not yet been setup.  Please initialize first.");
        }
    }
    /*
        displayResults() displays the raw data for the survey
    */
    public void Results()
    { 
        System.out.println("Displaying data results for "" + surveyName + ""n");
        for(int i = 0;i < numQuestions; i ++)
        {
            questions[i].displayResults();
            System.out.println();
        }
    }
    /*
        displayReportSummary() should run tests on your data 
        Examples could be: the most common response (median), the average response (mean), or display a graph of the results?
        The choices are endless!
    */
    public void reportSummary()
    {
        for(int i=0;< numQuestions; i ++)
        {
            if (questions[i] instanceof (DoubleQuestions)
                    {
                        DoubleQuestions temp = (DoubleQuestions) questions[i];
                        temp.doubleAverage();
                    System.out.println();
                    }
        }
    }

}

双重问题:

package survey;

import java.util.Scanner;

public class DoubleQuestions extends Question 

{
        private double[] responses;

    public DoubleQuestions(double q, int m)
        {
            super(Double.toString(q),(m)); 
            responses = new double[m];
        }
        @Override
        public void askQuestion()
        {
            double response;            
            Scanner input = new Scanner(System.in);
            System.out.print(question + " ");
            input.nextLine(); //still have to "eat" the current response          
            response = input.nextDouble(); 
            responses[numResponses] = response;
            numResponses++;
        }
        @Override
        public void displayResults()
        {
            System.out.println(question);
            for(int i = 0; i < numResponses;i++)
                System.out.println(responses[i]);
        }
}

在此循环中您有三个错误。

这一行中的一个:

for(int i=0;< numQuestions; i ++)

在这里您错过条件< numQuestions

此行中的另一个:

if (questions[i] instanceof (DoubleQuestions)

在这里您错过了关闭括号)

但是

if (questions[i] instanceof (DoubleQuestions))

上线应为:

if (questions[i] instanceof DoubleQuestions)

修复它:

for(int i=0; i < numQuestions; i ++)
{
    if (questions[i] instanceof DoubleQuestions)
            {
                DoubleQuestions temp = (DoubleQuestions) questions[i];
                temp.doubleAverage();
            System.out.println();
            }
}

您的doubleAverage()方法也未在DoubleQuestions类中实现。因此您无法从中参考。

所以您不能这样做:

DoubleQuestions temp = (DoubleQuestions) questions[i];
temp.doubleAverage();

首先实现doubleAverage()。然后尝试。

您应该尝试了解编译器向您投掷的错误消息。它清楚地说明了行号以及您在代码中犯了什么错误。

您需要关闭IF条件的paranthess:

if (questions[i] instanceof (DoubleQuestions)

必须是

if (questions[i] instanceof (DoubleQuestions)) 

您的for环路在此条件下缺少i

    for(int i=0;< numQuestions; i ++)

必须是:

    for(int i=0;i < numQuestions; i ++)

public void reportSummary()
{
    for(int i=0;< numQuestions; i ++)
    {
        if (questions[i] instanceof (DoubleQuestions)) // This line
                {
                    DoubleQuestions temp = (DoubleQuestions) questions[i];
                    temp.doubleAverage();
                System.out.println();
                }
    }
}

希望这会有所帮助!

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