Question

我是大学新生，目前是我计算机程序设计课程的第一个学期;我们已经开始同时使用伪代码和Java。

我们的任务是创建一个java应用程序，该应用程序总计并创建一系列由用户输入的数字的平均值。用户可以输入任意数量的数字，直到输入数字0，在这种情况下，程序输出总数和平均值，然后提示用户重新开始或退出程序。

我使用两个while循环完成了这个任务，其中一个是嵌套的。但是，当试图打破嵌套循环时，我收到错误“错误：打开外部开关或循环”。之后，我花了很多时间浏览这个论坛，寻找有关问题的答案和信息，但似乎没有一个与我的问题相关，并且修复不起作用。其中包括使用带标签的断裂和修正花括号;因为这些似乎不起作用，我确信这个问题在代码中更深层次。

因为我的课程是在线的，所以很难及时与教授或其他学生沟通，这就是我转向这个社区的原因！

下面我将附上教授希望我们将应用程序作为基础的伪代码。

Start
Declarations
Num sumTotal = 0  // Initialize for clarity
Num numEntered
Num averageNum
Num loopCounter
Num answer
String endProgram = “Y” // Initialize so that outer loop will work
    End declarations
// Greet the user
Output “Welcome to our calculator. “
Output “Enter as many numbers as you want.”
Output “When you are done entering numbers, enter 0 (zero) to display the sum.”
Output “Do you want to start the calculator? (Y/N): “  // Let the user   decide to start
input endProgram
// Note: if the user enters anything but Y or y, the loop will not execute. 
While endProgram <> “Y” OR endProgram <> “y”  // Allows the user to perform multiple calculations
//Enter the first number (sentinel value)
Output “Please enter your first number.”
Input numEntered
While numEntered <> 0  // Allows the user to enter numbers for the current calculation
    Output “You entered the number “ + numEntered  // echo input
    sumTotal = sumTotal + numEntered  // Add number entered to total
        loopCounter++ // Increment the number of entries
Output “Please enter the next number”
Input numEntered  // If 0, the loop will end here
endWhile // the nested inner loop code stops here
// Output section
Output “The total numbers entered is: “ + loopCounter
Output “The total of the numbers entered is: “ + sumTotal
Output “The average of the numbers entered is: “ + averageNum
Output “Would you like to do a new set of calculations? Y/N
Input endProgram
    End While // End outer While statement when endProgram = Y
    Output “Thank you for using the calculator. The program will now end.”      
Stop // Stop the program

下面我将附上我的Java代码

/* Module 4 Assignment 1 Part 1
* Aaron Field
* Submitted March 26, 2016
* Using DrJava */

import javax.swing.JOptionPane;
public class Calculator {

  public static void main(String[] args) {

    //variable declarations
    int numEntered;
    int sumTotal = 0;
    int averageNum = sumTotal / numEntered;
    int loopCounter;
    String endProgram = "Y";
    //end declarations

    System.out.println("Welcome to the Totaling Calculator");
    System.out.println("This program will accept integer inputs until 0 is entered" + '\n' + "When 0 is entered, a sum and an average will be displayed.");

endProgram = JOptionPane.showInputDialog(
                            "Do you want to start the calculator? (Y/N): ");

while(endProgram != "Y" || endProgram != "y"); {
        numEntered = Integer.parseInt(JOptionPane.showInputDialog(
                                    "Please enter your first number."));
        while(numEntered != 0); {
          System.out.println("You entered the number " + numEntered);
                               sumTotal = sumTotal + numEntered;
                               loopCounter++;
                             numEntered = Integer.parseInt(JOptionPane.showInputDialog(
                                                                      "Please enter the next number")); 
                             break;}


        System.out.println("The total numbers entered is: " + loopCounter + '\n' + "The total of the numbers entered is: " + sumTotal + '\n' + "The average of the numbers entered is: " + averageNum);

        endProgram = JOptionPane.showInputDialog(
                                                 "Would you like to do a new set of calculations? (Y/N): ");
        break;
}

System.out.println("Thank you for using the calculator. The program will now end.");
                   }
}

我理解代码可能很草率或奇怪，但我从2月中旬开始只使用Java，所以请原谅任何草率的格式或错误使用代码。

对于我未经训练的眼睛，休息陈述似乎在循环中;我很困惑为什么我的编译器会建议它们不是。非常感谢任何帮助，谢谢。

Answer 1

while（...）; 这是一种不好的做法：P。你的break命令实际上都在while循环之外。

Answer 2

在while语句后删除分号。

示例：更改

--rollStep

到

while(endProgram != "Y" || endProgram != “y”); {
//...
}

while语句后跟分号实际上被解释为此

while(endProgram != "Y" || endProgram != “y”) {
//...
}

Java：编译有关中断的错误

2 个答案: