Question

有人可以帮我弄清楚为什么while语句不起作用？在i = 3之后循环确实停止但是如果continueSurvey = 0则不会停止。它运行但如果我将continueSurvey更改为O则不会退出循环。即使我进入进程并且我可以看到变量是0，循环继续。

import java.util.Scanner;

public class SurveyConductor 
{

    public static void main(String[] args) 
    {
        Survey a = new Survey(); 
        a.display();

        a.enterQuestions();   

        int continueSurvey = 1;
        int i = 0;

            while ((continueSurvey != 0) && (i < 3))
            {

                for (int row = a.getRespID(); row < 3; row++)
                {

                    System.out.println("Respondent " + (row+1) + " Please tell us how you would rate our: ");

                    for (int col = 0; col < 3; col++)
                    {
                        Scanner input = new Scanner(System.in);

                        System.out.println(a.presentQuestion(col) + ": ");
                        System.out.println("Enter your response (1-Strongly Disagree, 2-Disagree, 3-Neutral, 4-Agree, 5-Strongly Agree): ");
                        int response = input.nextInt();

                        if ((response < 1) || (response >5))
                        {
                            while ((response < 1) || (response > 5))
                            {
                                System.out.println("Your response must be between 1 and 5. Please try again.");

                                System.out.println(a.presentQuestion(col) + ": ");
                                System.out.println("Enter your response (1-Strongly Disagree, 2-Disagree, 3-Neutral, 4-Agree, 5-Strongly Agree): ");
                                response = input.nextInt();
                            } 
                        }

                        a.logResponse(row,col,response);
                        System.out.println();
                    }

                    a.displaySurveyResults();
                    System.out.println();
                    System.out.println("The top rated question is Question #" + a.topRatedQuestion() + ".");
                    System.out.println("The bottom rated question is Question #" + a.bottomRatedQuestion() + ".");
                    System.out.println();

                    Scanner input2 = new Scanner(System.in);
                    System.out.println("Are there any more repondents (0 - No, 1 - Yes): ");
                    continueSurvey = input2.nextInt(); 


                    a.generateRespondentID();
                    i++;
                }
            } 
    }
}

Answer 1

您需要在break循环中添加for。 IE，

if(continueSurvey == 0)
    break;

这将退出for循环并允许while循环退出。

Answer 2

您询问用户是否要继续的部分位于此for循环

中

for (int row = a.getRespID(); row < 3; row++)

不只是你的while循环。这意味着它会一直询问，直到for循环完成，只有当它最终回到while循环条件时才会退出。

Answer 3

你在while循环中的条件是：

((continueSurvey != 0) && (i < 3))

这意味着当且仅当continueSurvey！= 0且i <1时，才会执行while循环的内部块。 3在同一时间。你有内环，有不同的条件。我会使用调试器在内部循环中搜索问题。如果这个答案对你来说还不够，那么请说明你想要达到的目标。

Answer 4

如果你想要在continueSurvey为0或i = 3时退出循环你必须像这样编写while循环：

while((continueSurvey != 0) || (i < 3)) {
    ...
}

＆amp;＆amp;＆amp; （和）运算符表示两个条件都必须为真，以便循环不退出其中一个（||或）。

在具有多个条件的Java循环中

4 个答案: