我的代码几近完美......我想。我需要输入用户输入的测试分数（最多50分）然后当用户输入-1时，它将显示他们输入的所有分数从最低到最高排序，然后在列表的底部排序说“平均值 _ _”。不幸的是，当我运行它时，我得到一个0的大量列表，我无法弄清楚我哪里出错了。如果有人有任何想法我会很感激
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import java.text.DecimalFormat;
public class AverageGrades extends JFrame
{
//construct conponents
static JLabel title = new JLabel("Average of Grades");
static JTextPane textPane = new JTextPane();
static int numberOfGrades = 0;
static int total = 0;
static DecimalFormat twoDigits = new DecimalFormat ("##0.00");
//set array
static int[] grades = new int[50];
//create content pane
public Container createContentPane()
{
//create JTextPane and center panel
JPanel northPanel = new JPanel();
northPanel.setLayout(new FlowLayout());
northPanel.add(title);
JPanel centerPanel = new JPanel();
textPane = addTextToPane();
JScrollPane scrollPane = new JScrollPane(textPane);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setPreferredSize(new Dimension(500,200));
centerPanel.add(scrollPane);
//create Container and set attributes
Container c = getContentPane();
c.setLayout(new BorderLayout(10,10));
c.add(northPanel,BorderLayout.NORTH);
c.add(centerPanel,BorderLayout.CENTER);
return c;
}
//method to add new text to JTextPane
public static JTextPane addTextToPane()
{
Document doc = textPane.getDocument();
try
{
// clear previous text
doc.remove(0,doc.getLength());
//insert title
doc.insertString(0,"Grades\n",textPane.getStyle("large"));
//insert grades and calculate average
for(int j=0; j<grades.length; j++)
{
doc.insertString(doc.getLength(), grades[j] + "\n", textPane.getStyle("large"));
}
}
catch(BadLocationException ble)
{
System.err.println("Couldn't insert text");
}
return textPane;
}
//method to sort array
public void grades(int grdArray[])
{
//sort int array
for (int pass = 1; pass<grdArray.length; pass++)
{
for (int element = 0; element<grdArray.length -1; element++)
{
swap(grades, element, element + 1);
}
}
addTextToPane();
}
//method to swap elements of array
public void swap(int swapArray[], int first, int second)
{
int hold;
hold = swapArray[first];
swapArray[first] = swapArray[second];
swapArray[second] = hold;
}
//execute method at run time
public static void main(String args[])
{
JFrame.setDefaultLookAndFeelDecorated(true);
AverageGrades f = new AverageGrades();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//accept first grade
int integerInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Please enter a grade (0-100) or -1 to calculate the average"));
//while loop accepts more grades, keeps count, and calulates the total
int count = 0;
int[] grades = new int[50];
int num = 0;
while (count<50 && num!= -1)
{
num = Integer.parseInt(JOptionPane.showInputDialog(null, "Please enter a grade (0-100) or -1 to calculate the average" + (count+1)));
if(num!=-1)
grades[count] = num;
count++;
}
//create content pane
f.setContentPane(f.createContentPane());
f.setSize(600,375);
f.setVisible(true);
}
}
答案 0 :(得分：1)
您定义了grade array两次：一次在class内：
static int[] grades = new int[50];
然后在main()：
int[] grades = new int[50];
答案 1 :(得分：0)
以下是解决您问题的更正代码。
有两个主要问题，您使用的是本地数组成绩而不是静态全局数组成绩。 （所以从main中删除声明）
其次，你永远不会插入导致第一个元素丢失的第一个值integerInput。
import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;
import java.text.DecimalFormat;
class AverageGrades extends JFrame {
// construct conponents
static JLabel title = new JLabel("Average of Grades");
static JTextPane textPane = new JTextPane();
static int numberOfGrades = 0;
static int total = 0;
static DecimalFormat twoDigits = new DecimalFormat("##0.00");
// set array
static int[] grades = new int[50];
// create content pane
public Container createContentPane() {
// create JTextPane and center panel
JPanel northPanel = new JPanel();
northPanel.setLayout(new FlowLayout());
northPanel.add(title);
JPanel centerPanel = new JPanel();
textPane = addTextToPane();
JScrollPane scrollPane = new JScrollPane(textPane);
scrollPane
.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setPreferredSize(new Dimension(500, 200));
centerPanel.add(scrollPane);
// create Container and set attributes
Container c = getContentPane();
c.setLayout(new BorderLayout(10, 10));
c.add(northPanel, BorderLayout.NORTH);
c.add(centerPanel, BorderLayout.CENTER);
return c;
}
// method to add new text to JTextPane
public static JTextPane addTextToPane() {
int counter = 0;
Document doc = textPane.getDocument();
try {
// clear previous text
doc.remove(0, doc.getLength());
// insert title
doc.insertString(0, "Grades\n", textPane.getStyle("large"));
//BREAKING IF NUMBER IS 0, SIGNIFIES THAT ALL ELEMENTS ARE COVERED
//counter IS USED TO CALCULATE THE TOTAL NUMBER OF ELEMENTS
// insert grades and calculate average
for (int j = 0; j < grades.length; j++) {
if (grades[j] != 0) {
doc.insertString(doc.getLength(), grades[j] + "\n",
textPane.getStyle("large"));
counter++;
} else {
break;
}
}
//THIS LINE INSERTS THE AVERAGE IN THE PANEL
doc.insertString(doc.getLength(), "Average is :"
+ (total / counter) + "\n", textPane.getStyle("large"));
} catch (BadLocationException ble) {
System.err.println("Couldn't insert text");
}
return textPane;
}
//CORRECT THE SORTING FUNCTION
// THE SORTING SHOULD BE IN REVERSE ORDER FOR YOUR REQUIREMENTS
// method to sort array
public void grades(int grdArray[]) {
// sort int array
for (int pass = 1; pass < grdArray.length; pass++) {
for (int element = 0; element < grdArray.length - 1; element++) {
swap(grades, element, element + 1);
}
}
addTextToPane();
}
// method to swap elements of array
public void swap(int swapArray[], int first, int second) {
int hold;
hold = swapArray[first];
swapArray[first] = swapArray[second];
swapArray[second] = hold;
}
// execute method at run time
public static void main(String args[]) {
JFrame.setDefaultLookAndFeelDecorated(true);
AverageGrades f = new AverageGrades();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// accept first grade
int integerInput = Integer.parseInt(JOptionPane.showInputDialog(null,
"Please enter a grade (0-100) or -1 to calculate the average"));
// while loop accepts more grades, keeps count, and calulates the total
int count = 0;
grades[0] = integerInput;
count++;
int num = 0;
while (count < 50 && num != -1) {
num = Integer.parseInt(JOptionPane.showInputDialog(null,
"Please enter a grade (0-100) or -1 to calculate the average"
+ (count + 1)));
//USING TOTAL FIELD TO CALCULATE SUM
if (num != -1) {
grades[count] = num;
total += grades[count];
}
count++;
}
//CALL THE SORTING FUNCTION AFTER CORRECTING IT
//f.grades(grades);
// create content pane
f.setContentPane(f.createContentPane());
f.setSize(600, 375);
f.setVisible(true);
}
}