【问题标题】:Understand what is going on with my Prime Numbers Calculation and Prime Numbers JFrame [closed]了解我的素数计算和素数 JFrame [关闭]
【发布时间】:2013-03-30 03:38:34
【问题描述】:

我想弄清楚我的代码出了什么问题,并帮助了解我的质数计算和质数JFrame 发生了什么。

  1. 出于某种原因,计算一只是说 1-100 的素数是
    1. 我取出了system.exit(0);,现在我需要在退出之前单击所有数字。我希望实现的是获得一个列出所有素数 1-100 的列表。
  2. 然后通过编码素数计算,我需要制作一个素数JFrame。我的错误太多,这是我的第一个问题,其次,由于错误,我无法运行项目来查看它。

我已将我的代码发布到素数计算和JFrame。任何帮助弄清楚发生了什么/错误将不胜感激。

*********************************************************************************
//Prime Numbers Java Swing JFrame
**********************************************************************************

 import javax.swing.*;
 import java.awt.*;
 import java.awt.event.*;


 public class ProgrammingAssignment8 extends JFrame 
 implements ActionListener 
 {

//DECLARE BUT DO NOT INSTANTIATE
private JButton calculate;
private JButton clear;
private JButton exit;

//PANELS
private JPanel jpnlMain = new JPanel();

private JPanel jpnlTop = new JPanel();
private JPanel jpnlCenter = new JPanel();
private JPanel jpnlBotton = new JPanel();

private JScrollPane scrollingResult;


//DECLARE JFRAME COMPONENTS
private JLabel jlblName, jlblMaxTest;
private JTextField jtfName, jtfMaxTest;
private JTextArea jtaName, jtaMaxNumbers;
private JButton jbutCalculate, jbutClear, jbutExit;

private CalculateButtonHandler calculateHandler;
private ClearButtonHandler clearHandler;
private ExitButtonHandler exitHandler;





/**
 * @param args
 */

//CLASS CONSTRUCTOR 
public ProgrammingAssignment8 (String sTitle) 
{       

//PREPARE THE JFRAME/WINDOW
    super(sTitle);
//SET TITLE AND SIZE
setTitle(sTitle);
setSize(400,400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//SET THE LAYOUT
jpnlMain.setLayout(new GridLayout(3,3,5,5));

 //INSTANTIATE THE JBUTTONS WITH THE PASSED CAPTION AND COLOR AND ADD TO JPANEL
//PUT INTO A METHOD FOR EFFICIENCY AND TO AVOID REPEATING ALL THE CODE
jbtnCalculate = instantiateJButton("Calculate", Color.red);
jbtnClear = instantiateJButton("Clear", Color.blue);
jbtnExit = instantiateJButton("Exit", Color.black);

//INSTANTIATE THE JLABEL COMPONENTS
jlblName = new JLabel ("");

//PREPARE THE CONTAINER
Container ca = getContentPane();
}

set visible(true);


//END CONSTRUCTOR


private JButton instantiateJButton(String, sInCaption, Color inColor)
{
JButton jbtnButton = new JButton(sInCaption);
jbtnButton.setActionCommand(sInCaption);
jbtnButton.addActionListener(this);
jbtnButton.setForeground(inColor);
jbtnButton.setFont(fontChosenFont);
jpnlMain.add(jbutnButton);
return jbtnButton;

//END INSTANTIATE JBUTTON

//CLASS EVENT HANDLER   
public void actionPerformed(java.awt.event.ActionEvent e)

{
    //FIND OUT WHICH BUTTON WAS PRESSED BY USING THE ACTION COMMAND VALUE
    String sActionCommand = e.getActionCommand();

    //FROM THE ACTIONEVENT OBJECT, GET AN INSTANCE OF THE JBUTTON THAT WAS PRESSED
    JButton jbtnSource = (JButton) e.getSource();

    jbtnSource.setEnabled(false);

    //LET THE USER KNOW WHAT BUTTON WAS CLICKED
    JOptionPane.showMessageDialog(null,  "You pressed the "" sActionCommand + " button", this.getTitle(), JOptionPane.INFORMATION_MESSAGE);
}

//END ACTIONPERFORMED (java.awt.event.ActionEvent e)

//EXECUTION STARTING POINT

public static void main(String[] args)
{
    ProgrammingAssignment8 = new ProgrammingAssignment8("Instantiates with a Method");

}
//END main(String[] args)


}
//END ProgrammingAssignment8 CLASS


***********************************************************************************
PRIME NUMBERS CALCULATIONS
***********************************************************************************

import javax.swing.JOptionPane;
public class ProgrammingAssignment7 
{

/**
 * @param args
 * @return 
 */
public static void main(String[] args) 
{
    //Scanner Scan = new Scanner (System.in);
    // TODO Auto-generated method stub

    //DECLARE VARIABLES
    int x = 1;
    int i = 1;
    int iNumber = 1;
    boolean bNotPrime = false;
    boolean bIsPrime = true;
    int iNumberToTest;
    int iPrimeCheck;
    int iCounter;
    int iResult = 1;
    int iFact = 1;
    int iLimit = 100;
    String OutputStr = null;





    System.out.println("Prime numbers between 1 and " + iLimit);

    //loop through the numbers one by one
    for(i=1; i < 100; i++)
    {

            bIsPrime = true;

            //check to see if the number is prime
            for(int j = 2; j < i ; j++){

                    if(i % j == 0){
                            bIsPrime = false;
                            break;
                    }
            }
            // print the number
            if(bIsPrime)

                OutputStr = "The Prime Numbers of 1 - 100 are: " + i + "\n";

                JOptionPane.showMessageDialog(null, OutputStr, "PRIME NUMBERS", JOptionPane.INFORMATION_MESSAGE);
                   //System.out.print(i + "\n" );






    //LISTS NUMBERS 1 THROUGH 100, INITIALIZE INTEGER NAMED I, IF IT IS LESS THAN OR EQUAL TO 100 THEN ADD ONE TO THE LOOP



    /* for (int i=1; i<=100; i++)
    {
        System.out.println(i);
    }



    /* iNumber = 7;

    for (iNumber = 1; iNumber <= 100; iNumber++)
        iResult = iNumber / 1;
    System.out.println(iResult);

    /* for ( iNumber = 2; iNumber <= 100; iNumber++ )
    {
      if ( iNumber % iNumber == 0 )
      {
        bIsPrime = false;
    break;

      }
    }

    return bIsPrime;
}

*/





    /* iNumber = 1; 
    while (iNumber < 100) iNumber++; 
    { 
        System.out.print(iNumber + " ");
        System.out.println();


        for (iNumber = iNumber - 1; iNumber > 2; iNumber++) 
        { //divides the number by each number less than the number itself and also greater than 1 (because 1 is a factor of every number, and every number is a factor of itself)
            if (iNumber % iNumber != 0) 
                System.out.println(iNumber + " is a prime number.");




            { //else if the number is evenly divisible by a number other than itself and 1 (we weeded out those cases in the above for statement), then it sets the boolean to be true, and breaks the for loop
                bNotPrime = false;
                iNumber = 1;
            }

        }

        if (bIsPrime = true) 
        { //if the number is not not a prime, then it prints the number and the for loop moves on 

        }

        else if (bNotPrime = false)
        { //otherwise the for loop moves on
            System.out.println(iNumber + " is not a prime number.");

            */              


}
}
}

【问题讨论】:

  • 您开始检查从 j=2 开始的素数,这会自动将 IsPrime 设置为 i = 1。
  • “由于错误,我无法运行项目来查看它。” 修复第一个问题,然后查看@NPE 的运行时建议。这似乎“过于宽泛”。顺便说一句 - 首先使用 Scanner 在命令行中工作,以检查逻辑。然后弄清楚如何将其转换为 GUI。
  • 通常,当我修复“正确的事情”时,所有错误都会消失。这一次,我不确定要解决什么问题。我现在也在使用调试器来尝试。我希望有人能够查看我所做的工作并指导我了解导致问题的原因以及我做错了什么。

标签: java swing primes prime-factoring


【解决方案1】:
  • set visible(true); 在构造函数之外并且不是有效的方法名称,它应该是 setVisible(true);,向上移动,使其出现在当前上方的 } 之前...
  • private JButton instantiateJButton(String, sInCaption, Color inColor) 不是一个有效的方法签名,你在 String 之后添加了一个 ,,它不需要,它应该是 private JButton instantiateJButton(String sInCaption, Color inColor)
  • JOptionPane.showMessageDialog(null, "You pressed the "" sActionCommand + " button", this.getTitle(), JOptionPane.INFORMATION_MESSAGE); 缺少 + 并且有太多 "。我认为应该是JOptionPane.showMessageDialog(null, "You pressed the " + sActionCommand + " button", this.getTitle(), JOptionPane.INFORMATION_MESSAGE);
  • ProgrammingAssignment8 = new ProgrammingAssignment8("Instantiates with a Method"); 不是一个有效的分配,你实际上并没有将值分配给任何东西......像ProgrammingAssignment8 assignment = new ProgrammingAssignment8("Instantiates with a Method"); 这样的东西会解决它。

以下不是有效的评论...

***********************************************************************************
PRIME NUMBERS CALCULATIONS
***********************************************************************************

这是……

/***********************************************************************************
PRIME NUMBERS CALCULATIONS
***********************************************************************************/
  • 我没有CalculateButtonHandlerClearButtonHandlerExitButtonHandlerjbtnCalculatejbtnClearjbtnExitfontChosenFont 的定义,所以我无法评论,不用说,它不会工作直到他们被写出来......

【讨论】:

    【解决方案2】:

    您可以做的是将质数存储在一个集合中。看看例如 ArrayList。它就像一个数组,但会动态增长,因此您不必提前指定大小。

    你有一个可以向用户展示该列表的列表。

    【讨论】:

    • “查看例如 ArrayList” 或者改为使用 Generic List 并使用最适合的任何可扩展容器。在这种“(Swing)GUI 中的列表”的特殊情况下,可能很奇怪Vector 更可取,因为JList(例如)具有接受Vector 的构造函数。 ;) 一般建议 +1。
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