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我試圖實現我的負/正按鈕，所以如果有人想輸入負數，他們可以但我的代碼有運行時錯誤。Java實現負/正按鈕狀態機計算器
似乎被卡在enterState6（）
我似乎無法得到它的爆發狀態6的繼續計算將我需要某種類型的循環？
package javacalculator;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.lang.Math.*;
public class JavaCalculator extends JFrame implements ActionListener
{
private final int ADD = 10;
private final int SUB = 11;
private final int MUL = 12;
private final int DIV = 13;
private final int EQL = 14;
private final int CLR = 15;
private final int NEG = 16;
private final int ERR = -1;
private JTextField display;
private int state = 0;
private double m0, m1;
private int op;
private JButton createButton(String tag)
{
JButton button = new JButton(tag);
button.setActionCommand(tag);
button.addActionListener(this);
return button;
}
public JavaCalculator()
{
display = new JTextField("0.0");
display.setHorizontalAlignment(JTextField.RIGHT);
display.setEditable(false);
display.setFont(new Font(display.getFont().getFontName(), display.getFont().getStyle(), 23));
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(6,6,3,3));
panel.setBorder(BorderFactory.createEmptyBorder(16, 16, 16, 16));
panel.add(createButton("7"));
panel.add(createButton("8"));
panel.add(createButton("9"));
panel.add(createButton("+"));
panel.add(createButton("4"));
panel.add(createButton("5"));
panel.add(createButton("6"));
panel.add(createButton("-"));
panel.add(createButton("1"));
panel.add(createButton("2"));
panel.add(createButton("3"));
panel.add(createButton("*"));
panel.add(createButton("0"));
panel.add(createButton("="));
panel.add(createButton("C"));
panel.add(createButton("/"));
panel.add(createButton("-/+"));
getContentPane().add(display, BorderLayout.NORTH);
getContentPane().add(panel, BorderLayout.CENTER);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Badass Calculator");
setSize(300, 300);
setVisible(true);
}
/**************************************************************************************************/
private int convertEvent(ActionEvent event)
{
if(event.getActionCommand().equals("0"))
return 0;
if(event.getActionCommand().equals("1"))
return 1;
if(event.getActionCommand().equals("2"))
return 2;
if(event.getActionCommand().equals("3"))
return 3;
if(event.getActionCommand().equals("4"))
return 4;
if(event.getActionCommand().equals("5"))
return 5;
if(event.getActionCommand().equals("6"))
return 6;
if(event.getActionCommand().equals("7"))
return 7;
if(event.getActionCommand().equals("8"))
return 8;
if(event.getActionCommand().equals("9"))
return 9;
if(event.getActionCommand().equals("+"))
return ADD;
if(event.getActionCommand().equals("-"))
return SUB;
if(event.getActionCommand().equals("*"))
return MUL;
if(event.getActionCommand().equals("/"))
return DIV;
if(event.getActionCommand().equals("="))
return EQL;
if(event.getActionCommand().equals("C"))
return CLR;
if(event.getActionCommand().equals("-/+"))
return NEG;
return ERR;
}
private boolean isNumber(int i)
{
return i >= 0 && i <= 9;
}
private boolean isOperation(int i)
{
switch(i)
{
case ADD:
case SUB:
case MUL:
case DIV: return true;
}
return false;
}
/***********************************************************************************************/
private void enterState0(int key)
{
state = 0;
m0 = 0;
display.setText(Double.toString(m0));
}
private void enterState1(int key)
{
state = 1;
m0 = m0 * 10 + key;
display.setText(Double.toString(m0));
}
private void enterState2(int key)
{
state = 2;
op = key;
m1 = 0;
}
private void enterState3(int key)
{
state = 3;
m1 = m1 * 10 + key;
display.setText(Double.toString(m1));
}
private void enterState4(int key)
{
state = 4;
switch(op)
{
case ADD: m1 = m0 + m1; break;
case SUB: m1 = m0 - m1; break;
case MUL: m1 = m0 * m1; break;
case DIV: m1 = m0/m1; break;
}
display.setText(Double.toString(m1));
m0 = 0;
}
private void enterState5(int key)
{
state = 5;
switch(op)
{
case ADD: m0 = m0 + m1; break;
case SUB: m0 = m0 - m1; break;
case MUL: m0 = m0 * m1; break;
case DIV: m0 = m0/m1; break;
}
display.setText(Double.toString(m0));
m1 = 0;
op = key;
}
private void enterState6(int key)
{
state = 6;
m0 = m0 * (-1);
display.setText(Double.toString(m0));
op = key;
m1 = 0;
}
public void actionPerformed(ActionEvent event)
{
int key = convertEvent(event);
switch(state)
{
case 0:
if(isNumber(key))
enterState1(key);
else if(key == NEG)
enterState6(key);
return;
//number
case 1:
if(key == CLR)
enterState0(key);
else if(isNumber(key))
enterState1(key);
else if(isOperation(key))
enterState2(key);
else if(key == NEG)
enterState6(key);
return;
//operator
case 2:
if(key == CLR)
enterState0(key);
else if(isNumber(key))
enterState3(key);
return;
//number
case 3:
if(key == CLR)
enterState0(key);
else if(isNumber(key))
enterState3(key);
else if(key == EQL)
enterState4(key);
else if(key == op)
enterState5(op);
else if(key == NEG)
enterState6(key);
return;
//equals
case 4:
if(key == CLR)
enterState0(key);
else if(isNumber(key))
enterState1(key);
else if(key == op)
enterState5(op);
return;
//equals + another number
case 5:
if(key == CLR)
enterState0(key);
else if(isNumber(key))
enterState3(key);
else if(key == NEG)
enterState6(key);
return;
}
}
/************************************************************************************/
public static void main(String[] args)
{
new JavaCalculator();
}
}
// negative numbers needs its own state m0 = m1 * -1
你是什麼意思卡住了？是否有堆棧跟蹤？ –