Does anyone know how you could process an equation, or even get an equation with more than two operands? Right now, in my calculator, I can only have two operands, and I want to have more.
Right here is what I have:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame implements ActionListener
{
JButton[] btnNums;
JButton btnBack;
JButton btnClear;
JButton btnCalculate;
String[] strNames;
String strOperand1;
String strOperand2;
Boolean wasClicked;
String answer;
double dd;
final String STR_MULTIPLY = "MULTIPLY";
final String STR_DIVIDE = "DIVIDE";
final String STR_ADD = "ADD";
final String STR_SUBTRACT = "SUBTRACT";
String whichOperator;
JTextField txtDisplay;
public Calculator()
{
Container content = getContentPane();
setSize(210,250);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
/* construct a JPanel and the textfield that
* will show the inputed values and outputed
* results
*/
JPanel jpDisplay = new JPanel();
jpDisplay.setLayout(new BorderLayout());
txtDisplay = new JTextField(15);
txtDisplay.setHorizontalAlignment(JTextField.RIGHT);
jpDisplay.add(txtDisplay);
/* contstruct a JPanel that will contain a back
* button and a clear button.
*/
JPanel jpRow2 = new JPanel();
btnBack = new JButton("Backspace");
btnBack.addActionListener(this);
btnClear = new JButton("Clear");
btnClear.addActionListener(this);
btnClear.addActionListener(this);
jpRow2.add(btnBack);
jpRow2.add(btnClear);
/* construct a string array with all the names of the
* buttons, then in a for loop create the new buttons
* and add their name and an actionListener to them.
*/
String[] strNames = {"7","8", "9","/", "4", "5", "6","*", "1",
"2", "3","+", "0", "+/-", ".", "-"};
btnNums = new JButton[16];
JPanel jpButtons = new JPanel();
jpButtons.setLayout(new GridLayout(4,4));
for (int i = 0; i < 16; i++)
{
btnNums[i] = new JButton(strNames[i]);
btnNums[i].addActionListener(this);
jpButtons.add(btnNums[i]);
}
/* construct the final JPanel and add a
* calculate button to it.
*/
JPanel jpLastRow = new JPanel();
btnCalculate = new JButton("Calculate");
btnCalculate.addActionListener(this);
jpLastRow.add(btnCalculate);
//make wasClicked have a default value of false
wasClicked = false;
/* set the contentPane and create the layout
* add the panels to the container
*/
setContentPane(content);
setLayout(new FlowLayout());
setResizable(false);
content.add(jpDisplay, BorderLayout.NORTH);
content.add(jpRow2);
content.add(jpButtons);
content.add(jpLastRow);
setTitle("Mini Calculator");
setVisible(true);
}
public void actionPerformed(ActionEvent ae)
{
// if any of the array buttons was clicked append the button's text
for (int i =0; i < 16; i++)
{
if (ae.getSource() == btnNums[i])
{
txtDisplay.setText(txtDisplay.getText()
+ btnNums[i].getText());
}
}
/* if the backspace button was clicked, then create substring
* to to subtract the farthest character to the right
*/
if (ae.getSource() == btnBack)
{
String strAll = txtDisplay.getText();
int length = strAll.length();
String strShowThis = strAll.substring(0,length - 1);
txtDisplay.setText(strShowThis);
}
else if (ae.getSource() == btnClear)
{
txtDisplay.setText(null);
}
else if (ae.getSource() == btnCalculate)
{
String strText = txtDisplay.getText();
try
{
int equation = Integer.parseInt(strText);
txtDisplay.setText("" + equation);
}
catch (ArithmeticException aee)
{
aee.printStackTrace();
}
}
/* start the process of finding which operator was
* chosen, and the process the equation in a new
* method
*/
if (ae.getSource() == btnNums[3])
{
processDivide();
}
else if (ae.getSource() == btnNums[7])
{
processMultiply();
}
else if (ae.getSource() == btnNums[11])
{
processAdd();
}
else if (ae.getSource() == btnNums[13])
{
processPosOrNeg();
}
else if (ae.getSource() == btnNums[15])
{
processSubtract();
}
else
{
}
// and finally process the calculation
if (ae.getSource() == btnCalculate)
{
processCalc();
}
else
{
}
}
public void processDivide()
{
whichOperator = STR_DIVIDE;
strOperand1 = txtDisplay.getText();
int x = strOperand1.length();
String s = strOperand1.substring(0, x - 1);
dd = Double.parseDouble(s);
txtDisplay.setText(null);
}
public void processMultiply()
{
whichOperator = STR_MULTIPLY;
strOperand1 = txtDisplay.getText();
int x = strOperand1.length();
String s = strOperand1.substring(0, x - 1);
dd = Double.parseDouble(s);
txtDisplay.setText(null);
}
public void processAdd()
{
whichOperator = STR_ADD;
strOperand1 = txtDisplay.getText();
int x = strOperand1.length();
System.out.println("variable x = " + x);
String s = strOperand1.substring(0, x - 1);
System.out.println("variable s = " + s);
dd = Double.parseDouble(s);
System.out.println("variable d = " + dd);
txtDisplay.setText(null);
}
public void processPosOrNeg()
{
}
public void processSubtract()
{
whichOperator = STR_SUBTRACT;
strOperand1 = txtDisplay.getText();
int x = strOperand1.length();
String s = strOperand1.substring(0, x - 1);
dd = Double.parseDouble(s);
txtDisplay.setText(null);
}
public void processCalc()
{
strOperand2 = txtDisplay.getText();
int x = strOperand2.length();
String s = strOperand2.substring(0, x);
double d = Double.parseDouble(s);
if (whichOperator == STR_SUBTRACT)
{
double a = dd - d;
txtDisplay.setText(dd + "-" + d + " = " + a);
}
else if (whichOperator == STR_ADD)
{
double a = dd + d;
txtDisplay.setText(dd + "+" + d + " = " + a);
}
else if (whichOperator == STR_MULTIPLY)
{
double a = dd * d;
txtDisplay.setText(dd + "*" + d + " = " + a);
}
else if (whichOperator == STR_DIVIDE)
{
double a = dd / d;
txtDisplay.setText(dd + "/" + d + " = " + a);
}
else
{
}
}
public static void main(String[] args)
{
Calculator calc = new Calculator();
}
}I'm welcome to anyother suggestions, and would appreciate them.
