Java postfix calculatrice push/pop méthode avec un String[] tableau

J'ai créé une nouvelle classe qui fait référence à un postfix calculatrice. Il utilise la push() et pop() méthodes. Voici le code (mise à Jour à partir de commentaires ci-dessous à l'aide d'un Générateur de Chaîne()):

import java.util.Stack;
import java.util.*;
import java.io.*;
public class StackCalculation 
{
public static void main (String[] args) throws Exception
{
String[] str = {"22+"};
String string = convertStringArrayToString(str);
System.out.println(string);
Stack<String> stack = new Stack<String>();
stack.add(string);
double a = 0;
double b = 0;
double sum = 0;
while (!stack.isEmpty())
{
if(stack.peek().equals("+"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a + b;
//Write something to push back the sum of the last 2 numbers a + b
stack.push("" + sum);
}
else if(stack.peek().equals("*"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a * b;
//Write something to push back the product of the last 2 numbers a * b
stack.push("" + sum);
}
else if(stack.peek().equals("-"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a - b;
//Write something to push back the difference of the last 2 numbers a - b
stack.push("" + sum);
}
else if(stack.peek().equals("/"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a / b;
//Write something to push back the quotient of the last 2 numbers a/b
stack.push("" + sum);
}
else 
{
//Convert the last item in the stack to a double and push
//this into the stack
String elem = stack.peek();
a = Double.parseDouble(elem);
stack.push("" + a);
}
}
System.out.println(stack);
//System.out.println(string);
}
private static String convertStringArrayToString(String[] strArr) {
StringBuilder sb = new StringBuilder();
for(String str : strArr) sb.append(str);
return sb.toString();
}

}

Lorsque j'exécute le code, il retourne ce message d'erreur:

    Exception in thread "main" java.lang.NumberFormatException: For input string: "22+"
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at StackCalculation.main(StackCalculation.java:69)

Il souligne:

        else 
{
//Convert the last item in the stack to a double and push
//this into the stack
String elem = stack.peek();
a = Double.parseDouble(elem);
stack.push("" + a);
}

J'ai essayé en passant par un Générateur de Chaîne méthode pour convertir le tableau de chaîne dans une chaîne.

La logique derrière postfix calcul est comme suit:

read in a symbol (number or operator)
As long as you’re not at the end of the entire string yet
if the symbol is +
pop the last 2 values from the stack
push back their sum
else if the symbol is *
pop the last 2 values from the stack and
push back their product
else if the symbol is –
pop the last 2 values from the stack and
push back the difference (second value – first value)
else if the symbol is /
pop the last 2 values from the stack
push back the quotient (second value / first value)
else if symbol is =
print the top of the stack
pop the stack
else if the symbol is a number
convert to a double and push it on the stack; read the next symbol, 
repeat above steps and do until you’re at the end of the string

Le programme complet est collé en dessous, je suis entrain de créer un GUI postfix calculatrice. J'ai dû utiliser la méthode split() dans la Chaîne de caractères à renvoyer la bonne getText() de sortie.

J'ai collé le code d'origine de l'interface graphique de l'opération ci-dessous. Je fais une nouvelle classe pour tester les résultats de la méthode suivante-

//Use the String's split method to get rid of spaces
public String[] getStringOutput()
{
String str = calculatorLabel.getText();
String[] string = str.split(" ");
return string;
}

Je suis le référencement de cette méthode à l'intérieur de la calcButtonListener() de la classe qui doit faire l'postfix calcul lorsque le bouton "Calculer" est cliqué.Je ne connais pas de toute façon d'écrire la classe privée calcButtonListener() à la fin.

import javax.swing.*;
import javax.swing.border.Border;
import java.util.Arrays;
import java.util.Stack;
import java.awt.*;
import java.awt.event.*;
public class PostfixCalculator extends JFrame
{
private JPanel calculatedResultPanel;
private JPanel northPanel;
private JPanel centerPanel;
private JPanel southPanel;
private JPanel num1Panel;
private JPanel num2Panel;
private JPanel num3Panel;
private JPanel num4Panel;
private JPanel num5Panel;
private JPanel num6Panel;
private JPanel num7Panel;
private JPanel num8Panel;
private JPanel num9Panel;
private JPanel addPanel;
private JPanel subtractPanel;
private JPanel multiplyPanel;
private JPanel dividePanel;
private JPanel zeroPanel;
private JPanel spacePanel;
private JPanel calculatePanel;
private JPanel clearPanel;
private JButton zero;
private JButton one;
private JButton two;
private JButton three;
private JButton four;
private JButton five;
private JButton six;
private JButton seven;
private JButton eight;
private JButton nine;
private JButton add;
private JButton subtract;
private JButton multiply;
private JButton divide;
private JButton space;
private JButton calculate;
private JButton clear;
private JLabel calculatorLabel;
private final int WINDOW_WIDTH = 350;
private final int WINDOW_HEIGHT = 250;
//Main
public static void main(String[] args)
{
new PostfixCalculator();
}
//Constructor
public PostfixCalculator()
{
setTitle("Posfix Calculator");
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Build the panel and add it to the frame
buildPanel();
//Get the string output from the buttons pressed
getStringOutput();
//Display the window
setVisible(true);
}
//The buildPanel method is created to add a label, text field,
//and a button to the panel
public void buildPanel()
{
//Use the insert containers method
insertContainers();
//Adjust the north panel to display the label bar
Border border = BorderFactory.createLineBorder(Color.BLACK, 1);
calculatorLabel.setBorder(border);
calculatorLabel.setPreferredSize(new Dimension(150, 25));
calculatedResultPanel.add(calculatorLabel);
northPanel.add(calculatedResultPanel);
add(northPanel, BorderLayout.NORTH);
//Adjust the east panel to display the majority
//of the buttons
centerPanel.setLayout(new GridLayout(4,4));
num1Panel.add(one);
num2Panel.add(two);
num3Panel.add(three);
addPanel.add(add);
num4Panel.add(four);
num5Panel.add(five);
num6Panel.add(six);
subtractPanel.add(subtract);
num7Panel.add(seven);
num8Panel.add(eight);
num9Panel.add(nine);
multiplyPanel.add(multiply);
zeroPanel.add(zero);
clearPanel.add(clear);
dividePanel.add(divide);
centerPanel.add(num1Panel);
centerPanel.add(num2Panel);
centerPanel.add(num3Panel);
centerPanel.add(addPanel);
centerPanel.add(num4Panel);
centerPanel.add(num5Panel);
centerPanel.add(num6Panel);
centerPanel.add(subtractPanel);
centerPanel.add(num7Panel);
centerPanel.add(num8Panel);
centerPanel.add(num9Panel);
centerPanel.add(multiplyPanel);
centerPanel.add(Box.createRigidArea(new Dimension(0,5)));
centerPanel.add(zeroPanel);
centerPanel.add(clearPanel);
centerPanel.add(dividePanel);
add(centerPanel, BorderLayout.CENTER);
//Put the remaining buttons and labels inside the South panel
southPanel.setLayout(new GridLayout(1,3));
calculatePanel.add(calculate);
spacePanel.add(space);
southPanel.add(Box.createRigidArea(new Dimension(0,5)));
southPanel.add(calculatePanel);
southPanel.add(spacePanel);
add(southPanel, BorderLayout.SOUTH);
//Add the action listeners to the panel
zero.addActionListener(new buttonListener());
one.addActionListener(new buttonListener());
two.addActionListener(new buttonListener());
three.addActionListener(new buttonListener());
four.addActionListener(new buttonListener());
five.addActionListener(new buttonListener());
six.addActionListener(new buttonListener());
seven.addActionListener(new buttonListener());
eight.addActionListener(new buttonListener());
nine.addActionListener(new buttonListener());
add.addActionListener(new buttonListener());
subtract.addActionListener(new buttonListener());
multiply.addActionListener(new buttonListener());
divide.addActionListener(new buttonListener());
space.addActionListener(new buttonListener());
clear.addActionListener(new buttonListener());
//Add the action listener for the calculate button
calculate.addActionListener(new buttonListener());
}
//Insert the panels, buttons and labels into the frame
public void insertContainers()
{
//Insert a label for the calculator output
calculatorLabel = new JLabel("");
//Create the panels
calculatedResultPanel = new JPanel();
northPanel = new JPanel();
centerPanel = new JPanel();
southPanel = new JPanel();
//Create the specialized panels
num1Panel = new JPanel();
num2Panel = new JPanel();
num3Panel = new JPanel();
num4Panel = new JPanel();
num5Panel = new JPanel();
num6Panel = new JPanel();
num7Panel = new JPanel();
num8Panel = new JPanel();
num9Panel = new JPanel();
addPanel = new JPanel();
subtractPanel = new JPanel();
multiplyPanel = new JPanel();
zeroPanel = new JPanel();
clearPanel = new JPanel();
dividePanel = new JPanel();
calculatePanel = new JPanel();
spacePanel = new JPanel();
//Create the buttons to be displayed
one = new JButton("1");
two = new JButton("2");
three = new JButton("3");
four = new JButton("4");
five = new JButton("5");
six = new JButton("6");
seven = new JButton("7");
eight = new JButton("8");
nine = new JButton("9");
add = new JButton("+");
subtract = new JButton("-");
multiply = new JButton("*");
zero = new JButton("0");
clear = new JButton("C");
divide = new JButton("/");
calculate = new JButton("Calculate");
space = new JButton("_");
}
//Use the String's split method to get rid of spaces
public String[] getStringOutput()
{
String str = calculatorLabel.getText();
String[] string = str.split(" ");
return string;
}
//Needed to convert the getStringOutput() method above from a String[] to a String.
private static String convertStringArrayToString(String[] strArr) {
StringBuilder sb = new StringBuilder();
for(String str : strArr) sb.append(str);
return sb.toString();
}
//Add the button pressed to the JLabel field
private class buttonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
//Determine which button was clicked and add this to the JLabel
if( e.getSource() == zero)
calculatorLabel.setText(calculatorLabel.getText() + "0");
if( e.getSource() == one)
calculatorLabel.setText(calculatorLabel.getText() + "1");
if( e.getSource() == two)
calculatorLabel.setText(calculatorLabel.getText() + "2");
if( e.getSource() == three)
calculatorLabel.setText(calculatorLabel.getText() + "3");
if( e.getSource() == four)
calculatorLabel.setText(calculatorLabel.getText() + "4");
if( e.getSource() == five)
calculatorLabel.setText(calculatorLabel.getText() + "5");
if( e.getSource() == six)
calculatorLabel.setText(calculatorLabel.getText() + "6");
if( e.getSource() == seven)
calculatorLabel.setText(calculatorLabel.getText() + "7");
if( e.getSource() == eight)
calculatorLabel.setText(calculatorLabel.getText() + "8");
if( e.getSource() == nine)
calculatorLabel.setText(calculatorLabel.getText() + "9");
if( e.getSource() == add)
calculatorLabel.setText(calculatorLabel.getText() + "+");
if( e.getSource() == subtract)
calculatorLabel.setText(calculatorLabel.getText() + "-");
if( e.getSource() == multiply)
calculatorLabel.setText(calculatorLabel.getText() + "*");
if( e.getSource() == divide)
calculatorLabel.setText(calculatorLabel.getText() + "/");
if( e.getSource() == space)
calculatorLabel.setText(calculatorLabel.getText() + " ");
if( e.getSource() == clear)
calculatorLabel.setText("");
}
//Create the calculator button action listener.
//Add the button pressed to the JLabel field
private class calcButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String[] str = getStringOutput();
String string = convertStringArrayToString(str);
Stack<String> stack = new Stack<String>();
stack.add(string);
double a = 0;
double b = 0;
double sum = 0;
while (!stack.isEmpty())
{
if(stack.peek().equals("+"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a + b;
//Write something to push back the sum of the last 2 numbers a + b
stack.push("" + sum);
}
else if(stack.peek().equals("*"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a * b;
//Write something to push back the product of the last 2 numbers a * b
stack.push("" + sum);
}
else if(stack.peek().equals("-"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a - b;
//Write something to push back the difference of the last 2 numbers a - b
stack.push("" + sum);
}
else if(stack.peek().equals("/"))
{
a = Double.parseDouble(stack.peek());
stack.pop();
b = Double.parseDouble(stack.peek());
stack.pop();
sum = a / b;
//Write something to push back the quotient of the last 2 numbers a/b
stack.push("" + sum);
}
else 
{
//Convert the last item in the stack to a double and push
//this into the stack
String elem = stack.peek();
a = Double.parseDouble(elem);
stack.push("" + a);
}
}
}
}
}

}