Question

我收到了一段过于复杂且效率极低的代码。我的任务是：

确定循环不会退出的原因

重新考虑此代码，使其效率更高。

        do
        {
            if(noOfQuest<1)
            {
                System.out.println("FILE_ERROR: Please ensure line \"noOfEmails\" is more than 0");
            }

            if(noOfQuest==1)
            {
                if(iCount==0)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(prefinalMess);
                    System.out.println(questionArr[0]);
                    ansArray[0]=ans.next();
                    System.out.println("Answer 1 where question is ["+noOfQuest+"]" +ansArray[0]);
                    if(IsAnswer1Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure you enter a response");
                        continue;
                    }
                    System.out.println(finalMess);
                }
            }
            if(noOfQuest==2)
            {
                if(iCount==0)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(questionArr[0]);
                    ansArray[0]=ans.next();
                    if(IsAnswer1Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you enter a response for question 1");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==1)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(prefinalMess);
                    System.out.println(questionArr[1]);
                    ansArray[1]=ans.next();
                    if(IsAnswer2Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you enter a response for question 2");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
            }

            if(noOfQuest==3)
            {
                if(iCount==0)
                {
                    System.out.println("Count is on [" +iCount+"]");
                    System.out.println(questionArr[0]);
                    ansArray[0]=ans.next();
                    if(IsAnswer1Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you enter a response for question 1");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==1)
                {
                    System.out.println(questionArr[1]);
                    ansArray[1]=ans.next();
                    if(IsAnswer2Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 2");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==2)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(prefinalMess);
                    System.out.println(questionArr[2]);
                    ansArray[2]=ans.next();
                    if(IsAnswer3Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 3");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
            }
            if(noOfQuest==4)
            {
                if(iCount==0)
                {
                    System.out.println("Count is on [" +iCount+"]");
                    System.out.println(questionArr[0]);
                    ansArray[0]=ans.next();
                    if(IsAnswer1Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you enter a response for question 1");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==1)
                {
                    System.out.println("Count is on [" +iCount+"]");
                    System.out.println(questionArr[1]);
                    ansArray[1]=ans.next();
                    if(IsAnswer2Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 2");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==2)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(questionArr[2]);
                    ansArray[2]=ans.next();
                    if(IsAnswer3Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 3");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==3)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(prefinalMess);
                    System.out.println(questionArr[3]);
                    ansArray[3]=ans.next();
                    if(IsAnswer4Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 3");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
            }
            if(noOfQuest==5)
            {
                if(iCount==0)
                {
                    System.out.println("Count is on [" +iCount+"]");
                    System.out.println(questionArr[0]);
                    ansArray[0]=ans.next();
                    if(IsAnswer1Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you enter a response for question 1");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==1)
                {
                    System.out.println("Count is on [" +iCount+"]");
                    System.out.println(questionArr[1]);
                    ansArray[1]=ans.next();
                    if(IsAnswer2Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 2");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==2)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(questionArr[2]);
                    ansArray[2]=ans.next();
                    if(IsAnswer3Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 3");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==3)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(questionArr[3]);
                    ansArray[3]=ans.next();
                    if(IsAnswer4Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 4");
                        continue;
                    }
                    iCount++;
                    System.out.println(finalMess);
                }
                if(iCount==4)
                {
                    System.out.println("Count is on ["+iCount+"]");
                    System.out.println(prefinalMess);
                    System.out.println(questionArr[4]);
                    ansArray[4]=ans.next();
                    if(IsAnswer5Blank(ansArray)==true)
                    {
                        System.out.println("Please ensure that you have entered a response for question 5");
                        continue;
                    }
                }
                iCount++;
                System.out.println(finalMess);
            }
            if(iCount==0)
            {
                if(noOfQuest==0)
                {
                    System.out.println("FILE_ERROR: Please ensure line \"noOfQuest\" in file is between 1 and 5." + "\n" +
                                        "File located: C:/Exercise 7 - Emails/configuration.properties");
                }
                iCount++;
                if(noOfQuest>5)
                {
                    System.out.println("FILE_ERROR: Please ensure line \"noOfQuest\" in file is between 1 and 5." + "\n" +
                                        "File located: C:/Exercise 7 - Emails/configuration.properties");
                }
                iCount++;
            }
            if(iCount==1)
            {
                break;
            }

            break;
        }
        while(true);

当变量“noOfQuest”设置为“0”时，应用程序按预期关闭。但是，当变量设置为大于5时，应用程序将挂起。我该如何解决这个问题？

修改

我已经编辑了这个问题，包括我最终使用的答案，下面是Lawrence Aiello建议的答案（接受答案）。

if(iCount==0)
            {
                if(noOfQuest==0 || noOfQuest>5)
                {
                    System.out.println("FILE_ERROR: Please ensure line \"noOfQuest\" in file is greater than 0." + "\n" +
                                        "File located: C:/Exercise 7 - Emails/configuration.properties");
                    System.exit(0);
                }
            }

重构为for-nested do-while循环以检查所有条件

Answer 1

因为你的程序处于无限循环中，只有当noOfQuest为0时才会退出。因此，如果它永远不会达到这个值，循环将永远继续，这导致你正在谈论的悬挂

在那里放置一个if语句，为noOfQuest处理大于5的值。

Answer 2

如果系统地检查不同的离散值（1,2,3，...），请使用switch case语句。还要添加默认路径，以免卡住。为您节省了大量代码。

Answer 3

我遇到的一个简单的解决方案是以下代码：

if(iCount==0)
                {
                    if(noOfQuest==0 || noOfQuest>5)
                    {
                        System.out.println("FILE_ERROR: Please ensure line \"noOfQuest\" in file is greater than 0." + "\n" +
                                            "File located: C:/Exercise 7 - Emails/configuration.properties");
                        System.exit(0);
                    }
                }

此部分检查iCount是否为0（始终在运行时）并检查问题的数量是0还是大于5.如果是，它将打印消息并关闭应用程序，使用“System.exit（ 0）”。此命令将关闭当前的JVM会话。

循环没有退出

修改

3 个答案: