Hello,
I'm creating a windows like calculator using Java, I seem to be having some problems..
It will let me calculate two numbers together e.g.
2 + 2 (It will display 4)
however, if I want to do multiple calculations... e.g.
2 + 2 + * 3
It will only still add the two numbers, which I have assigned to number1 and number2
Any suggestions?
would you kindly post the code so we can help, thanks
public class MycalDesign extends JFrame {
/**
*
*/
private static final long serialVersionUID = -1388448113487969657L;
private String numDisplayed;
private String digit;
private double number1;
private double number2;
private double result;
private double finalResult;
private double numCheck;
private boolean nextNum = true;
private double otherCalFunctions;
// private CalOp calculation = new CalOp();
private ArrayList<Double> op;
// private String [] listData = historyComputations.toArray(new
// String[historyComputations.size()]);
private JTextArea calDisplay;
private JTextArea formulaDisplay;
private JList historyList;
private JPanel insideCalPanel;
public static void main(String[] args) {
MycalDesign frame_1 = new MycalDesign();
frame_1.setVisible(true);
frame_1.setSize(300, 300);
frame_1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame_1.setResizable(false);
frame_1.pack();
}
public MycalDesign() {
super("Calculator");
getContentPane().setLayout(new BorderLayout());
insideCalPanel = new JPanel(new BorderLayout());
numPadGUI();
funcPadGUI();
memPadGUI();
historyMemoryList();
op = new ArrayList<Double>();
calDisplay = new JTextArea();
calDisplay.setEditable(false);
formulaDisplay = new JTextArea();
formulaDisplay.setEditable(false);
formulaDisplay.setBackground(new Color(195, 188, 188));
//formulaDisplay.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
calDisplay.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
calDisplay.setBackground(new Color(195, 188, 188));
// formulaDisplay.setForeground(Color.WHITE);
insideCalPanel.add(calDisplay, BorderLayout.NORTH);
getContentPane().add(insideCalPanel, BorderLayout.CENTER);
getContentPane().add(formulaDisplay, BorderLayout.NORTH);
}
public void numPadGUI() {
final ActionListener numPadListener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
digit = e.getActionCommand();
nextNum = false;
if (nextNum) {
calDisplay.setText(digit);
nextNum = true;
} else {
calDisplay.setText(calDisplay.getText() + digit);
numDisplayed = calDisplay.getText();
number1 = readDisplayNumber();
}
formulaDisplay.append(digit);
}
};
JPanel numPadPanel = new JPanel(new GridLayout(4, 3, 1, 1));
String numPad = "123456789.0C";
for (int i = 0; i < numPad.length(); i++) {
JButton numButton = new JButton(numPad.substring(i, i + 1));
numButton.addActionListener(numPadListener);
numPadPanel.add(numButton);
}
insideCalPanel.add(numPadPanel, BorderLayout.CENTER);
}
public void funcPadGUI() {
ActionListener funcPadListener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
String operator = e.getActionCommand();
actionClear();
if (operator.equals("+")) {
} else if (operator.equals("/")) {
formulaDisplay.append(" / ");
} else if (operator.equals("-")) {
formulaDisplay.append(" - ");
} else if (operator.equals("x")) {
formulaDisplay.append(" x ");
} else if (operator.equals("%")) {
} else if (operator.equals("sqrt")) {
} else if (operator.equals("x^2")) {
} else if (operator.equals("bk")) {
} else if (operator.equals("=")) {
if (numCheck == 1) {
calDisplay.setText(Double.toString(result));
} else if (numCheck == 2) {
} else if (numCheck == 3) {
} else if (numCheck == 4) {
}
}
}
};
JPanel funcPadPanel = new JPanel(new GridLayout(4, 1, 1, 1));
String[] funcPad = { "+", "sqrt", "x", "x^2", "-", "%", "/", "=" };
for (int i = 0; i < funcPad.length; i++) {
JButton funcButton = new JButton(funcPad[i]);
funcButton.addActionListener(funcPadListener);
funcPadPanel.add(funcButton);
}
insideCalPanel.add(funcPadPanel, BorderLayout.EAST);
}
public void memPadGUI() {
JPanel memPadPanel = new JPanel(new GridLayout(4, 1, 1, 1));
String[] memPad = { "MR", "MC", "M+", "M-" };
for (int i = 0; i < memPad.length; i++) {
JButton memButton = new JButton(memPad[i]);
memButton.addActionListener(memPadListener);
memPadPanel.add(memButton);
}
insideCalPanel.add(memPadPanel, BorderLayout.WEST);
}
public void actionClear() {
calDisplay.setText("");
}
public double readDisplayNumber() {
double num1;
num1 = Double.valueOf(numDisplayed);
return num1;
}
}
}Any help would be much appreciated, the empty if, else statements i'm guessing is where I need to do everything.
I've tried, and got it to work using two numbers but I have deleted that now..
Think of a calculator as having 3 parts:
left operand + operator + right operand.
5 + 3 * 2
5 is left, + is operator, 3 is right
perform calculation, send to output
Output becomes left operand.
so then you have 8 left, * operator, 2 right
perform calculation, send to output
if = is entered, it just repeats whatever is stored in left operand with operator and right operand.
One suggestion. Abstract out an "Operator" class that contains an abstract method execute(). Then you can create a method to create a JButton with an actionListener that invokes that abstract execute method.
We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.