Question

所以我现在一直在研究这段代码，在添加JOptionPane之前我测试了它并且有0个错误，然后我添加了JOptionPane并且在27-38之间。所以我在JOptionPane中明显做错了但是我不确定是什么，我只有大部分使用Scanner的经验所以任何帮助都会受到赞赏。谢谢！

import javax.swing.JOptionPane;
import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;

public class TestScores
{
    public static void main(String args[]) throws IOException {
        String filename = ("scores.txt");
        File file = new File(filename);
        Scanner inputFile = new Scanner(file);

        while (inputFile.hasNextInt()) {
            String line = inputFile.nextLine();
            ArrayList<Integer> scores = new ArrayList<Integer>();
            Scanner scanner = new Scanner(line);
            scanner.useDelimiter(",");

            while(scanner.hasNextInt()) {
                scores.add(scanner.nextInt());
            }

            scanner.close();
        }
    }

    public static int averageScore(int[] numbers) {
        int total = 0;
        for (int i : numbers) {
            total += i;
        }
        return total/(numbers.length);
    }

    public static int modeOfScores(int[] numbers) {
        int modeCount = 0;
        int mode = 0;     
        int currCount = 0;    
        int currElement;

        for (int candidateMode : numbers) {
            currCount = 0;

            for (int element : numbers) {
                if (candidateMode == element) {
                    currCount++;
                }
            }

            if (currCount > modeCount) {
                modeCount = currCount;
                mode = candidateMode;
            }
        }

        return mode;
    }

    public static int lowestScore(int[] numbers) {
        int lowest = numbers[0];

        for(int i = 1; i > numbers.length; i++) {
            if(numbers[i] < lowest) {
                lowest = numbers[i];
            }
        }
        return lowest;
    }

    public static int largestScore(int[] numbers) {  
        int largest = numbers[0];  
        for(int i = 1; i < numbers.length; i++) {  
            if(numbers[i] > largest) {  
                largest = numbers[i];  
            }
        }  
        return largest;
    }
    JOptionPane.showMessageDialog (null, "The Average number is: " + total);
    JOptionPane.showMessageDialog (null, "The Mode number is: " + mode);
    JOptionPane.showMessageDialog (null, "The Lowest number is: " + lowest);
    JOptionPane.showMessageDialog (null, "The Largest number is: " + largest);
}

编辑：以下是我得到的所有错误，全部来自JOptionPane部分

TestScores.java:86: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                ^
TestScores.java:86: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                 ^
TestScores.java:86: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                       ^
TestScores.java:86: error: ')' expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                ^
TestScores.java:86: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                  ^
TestScores.java:86: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                               ^
TestScores.java:86: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                                ^
TestScores.java:86: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                                 ^
TestScores.java:86: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Average number is: " +(averageScore));
                                                                                  ^
TestScores.java:87: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
              ^
TestScores.java:87: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                 ^
TestScores.java:87: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                       ^
TestScores.java:87: error: ')' expected
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                             ^
TestScores.java:87: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                               ^
TestScores.java:87: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                                            ^
TestScores.java:87: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                                             ^
TestScores.java:87: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                                              ^
TestScores.java:87: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Mode number is: " +(modeOfScores));
                                                                               ^
TestScores.java:88: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
              ^
TestScores.java:88: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                 ^
TestScores.java:88: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                       ^
TestScores.java:88: error: ')' expected
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                               ^
TestScores.java:88: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                                 ^
TestScores.java:88: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                                             ^
TestScores.java:88: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                                              ^
TestScores.java:88: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                                               ^
TestScores.java:88: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowestScore));
                                                                                ^
TestScores.java:89: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
              ^
TestScores.java:89: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                 ^
TestScores.java:89: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                       ^
TestScores.java:89: error: ')' expected
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                ^
TestScores.java:89: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                  ^
TestScores.java:89: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                               ^
TestScores.java:89: error: illegal start of type
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                                ^
TestScores.java:89: error: <identifier> expected
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                                 ^
TestScores.java:89: error: ';' expected
   JOptionPane.showMessageDialog(null, "The Largest number is: " +(largestScore));
                                                                                  ^
TestScores.java:90: error: reached end of file while parsing
}

^

Answer 1

首先是两个问题。你班上的最后4个方法调用都是松散的。

JOptionPane.showMessageDialog(null, "The Average number is: " +(total));
JOptionPane.showMessageDialog(null, "The Mode number is: " +(mode));
JOptionPane.showMessageDialog(null, "The Lowest number is: " +(lowest));
JOptionPane.showMessageDialog(null, "The Largest number is: " +(largest));

在这种情况下，他们需要在一个方法内。

第二个总计，模式，最低和最大只在其各自的方法范围内本地定义。

您需要将它们存储为TestScores的成员。

编辑＃1

小记，Java是用lowerCamelCase编写的http://en.wikipedia.org/wiki/CamelCase

编辑＃2

我完成了整个代码并注意到了很多错误。

Java中的array与ArrayList不同。所以你必须这样做选择一个，在这种情况下，ArrayList将为你做伎俩，如你可以更优雅地处理它。
ArrayList没有array所拥有的索引。相反，你必须使用它的方法get(index) 由.运算符访问。
当方法返回total，mode，lowest和largest的值时，为什么不调用它们直接在您的showMessageDialog()？

编辑＃3

我现在没有scores.txt进行测试。这不会产生编译错误。

import javax.swing.JOptionPane;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class TestScores
{
    public static void main(String args[]) throws IOException { 
        String filename = ("scores.txt");
        File file = new File(filename);
        Scanner inputFile = new Scanner(file);

        List<Integer> scores = new ArrayList<Integer>();

        while (inputFile.hasNextInt()) {
            String line = inputFile.nextLine();

            Scanner scanner = new Scanner(line);
            scanner.useDelimiter(",");

            while(scanner.hasNextInt()) {
                scores.add(scanner.nextInt());
            }

            scanner.close();
        }

        JOptionPane.showMessageDialog (null, "The Average number is: " + averageScore(scores));
        JOptionPane.showMessageDialog (null, "The Mode number is: " + modeOfScores(scores));
        JOptionPane.showMessageDialog (null, "The Lowest number is: " + lowestScore(scores));
        JOptionPane.showMessageDialog (null, "The Largest number is: " + largestScore(scores));
    }

    public static int averageScore(List<Integer> numbers) {
        int total = 0;
        for (int i : numbers) {
            total += i;
        }
        return total/(numbers.size());
    }

    public static int modeOfScores(List<Integer> numbers) {
        int modeCount = 0;
        int mode = 0;     
        int currCount = 0;    
        int currElement;

        for (int candidateMode : numbers) {
            currCount = 0;

            for (int element : numbers) {
                if (candidateMode == element) {
                    currCount++;
                }
            }

            if (currCount > modeCount) {
                modeCount = currCount;
                mode = candidateMode;
            }
        }

        return mode;
    }

    public static int lowestScore(List<Integer> numbers) {
        int lowest = numbers.get(0);

        for(int i = 1; i > numbers.size(); i++) {
            if(numbers.get(i) < lowest) {
                lowest = numbers.get(i);
            }
        }
        return lowest;
    }

    public static int largestScore(List<Integer> numbers) {  
        int largest = numbers.get(0);  
        for(int i = 1; i < numbers.size(); i++) {  
            if(numbers.get(i) > largest) {  
                largest = numbers.get(i);  
            }
        }  
        return largest;
    }
}

将.text导入Array，输出WITH / Dialog框

1 个答案: