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Added support for decimal numbers

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Norbi Peti 2016-07-13 13:50:34 +02:00
parent 5b48e82dc6
commit 5f1c3e0231
2 changed files with 78 additions and 16 deletions
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22
src/calculator/Calc.java
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@ -6,27 +6,31 @@ import java.util.regex.Pattern;
public class Calc {
private static final Pattern MULTIPLY = Pattern.compile("([0-9]+)\\*([0-9]+)");
private static final Pattern DIVIDE = Pattern.compile("([0-9]+)\\/([0-9]+)");
private static final Pattern ADD = Pattern.compile("([0-9]+)\\+([0-9]+)");
private static final Pattern SUBTRACT = Pattern.compile("([0-9]+)\\-([0-9]+)");
private static final Pattern MULTIPLY = Pattern.compile("([0-9\\.]+)\\*([0-9\\.]+)");
private static final Pattern DIVIDE = Pattern.compile("([0-9\\.]+)\\/([0-9\\.]+)");
private static final Pattern ADD = Pattern.compile("([0-9\\.]+)\\+([0-9\\.]+)");
private static final Pattern SUBTRACT = Pattern.compile("([0-9\\.]+)\\-([0-9\\.]+)");
public static int calculate(String text) {
public static Double calculate(String text) {
StringBuffer buf = new StringBuffer(text);
replace(buf, MULTIPLY, (a, b) -> a * b);
replace(buf, DIVIDE, (a, b) -> a / b);
replace(buf, ADD, (a, b) -> a + b);
replace(buf, SUBTRACT, (a, b) -> a - b);
return Integer.parseInt(buf.toString());
try {
return Double.parseDouble(buf.toString());
} catch (Exception e) {
return null;
}
}
private static void replace(StringBuffer buf, Pattern pattern, BiFunction<Integer, Integer, Integer> doit) {
private static void replace(StringBuffer buf, Pattern pattern, BiFunction<Double, Double, Double> doit) {
while (true) {
Matcher matcher = pattern.matcher(buf.toString());
if (!matcher.find())
break;
buf.replace(matcher.start(), matcher.end(), Integer
.toString(doit.apply(Integer.parseInt(matcher.group(1)), Integer.parseInt(matcher.group(2)))));
buf.replace(matcher.start(), matcher.end(), Double
.toString(doit.apply(Double.parseDouble(matcher.group(1)), Double.parseDouble(matcher.group(2)))));
}
}
}

72
src/calculator/Gui.java
View file

@ -5,9 +5,13 @@ import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
@ -20,27 +24,58 @@ public class Gui {
public Gui() throws Exception {
frame = new JFrame();
frame.setMinimumSize(new Dimension(200, 400));
frame.setMinimumSize(new Dimension(300, 400));
frame.setTitle("Calculator");
frame.setLayout(new BorderLayout(10, 10));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == '+')
tf.setText(tf.getText() + '+');
else if (e.getKeyChar() == '-')
tf.setText(tf.getText() + "-");
else if (e.getKeyChar() == '*')
tf.setText(tf.getText() + "*");
else if (e.getKeyChar() == '/')
tf.setText(tf.getText() + "/");
else if (e.getKeyChar() == '.')
tf.setText(tf.getText() + ".");
else if (e.getKeyChar() == '\n') {
calc();
} else if (e.getKeyChar() == '\b' && tf.getText().length() > 0)
tf.setText(tf.getText().substring(0, tf.getText().length() - 1));
else if (e.getKeyChar() >= '0' && e.getKeyChar() <= '9')
tf.setText(tf.getText() + e.getKeyChar());
}
@Override
public void keyReleased(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
}
});
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
tf = new JTextField();
tf.setFocusable(false);
frame.add(tf, BorderLayout.NORTH);
panel = new JPanel();
frame.add(panel, BorderLayout.CENTER);
panel.setLayout(new GridLayout(5, 3));
String str = addNumbers();
str += "+0-*/";
panel.setLayout(new GridLayout(4, 4));
String str = addNumbers("+-*");
str += ".0";
addAppendButtons(str);
addButton('=').addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
tf.setText(Integer.toString(Calc.calculate(tf.getText())));
calc();
}
});
addAppendButtons("/");
}
public void show() {
@ -51,10 +86,13 @@ public class Gui {
frame.dispose();
}
private String addNumbers() {
private String addNumbers(String rowend) {
String str = "";
int x = 0;
for (int i = 1; i < 10; i++) {
str += i;
if (i % 3 == 0)
str += rowend.charAt(x++);
}
return str;
}
@ -71,7 +109,7 @@ public class Gui {
tf.setText(tf.getText() + number);
}
});
}
}
}
private JButton addButton(Character c) {
@ -81,4 +119,24 @@ public class Gui {
panel.add(num);
return num;
}
private void calc() {
try {
Double ret = Calc.calculate(tf.getText());
if (ret == null)
JOptionPane.showMessageDialog(frame, "Unable to convert result to number!", "Error!",
JOptionPane.WARNING_MESSAGE);
else
tf.setText(Double.toString(ret));
} catch (ArithmeticException e) {
JOptionPane.showMessageDialog(frame, "Arithmetic error: " + e.getMessage(), "Error!",
JOptionPane.WARNING_MESSAGE);
} catch (NumberFormatException e) {
JOptionPane.showMessageDialog(frame,
"Number format error: " + e.getMessage() + "\n\nThe number may be too large.", "Error!",
JOptionPane.WARNING_MESSAGE);
} catch (Exception e) {
JOptionPane.showMessageDialog(frame, "Unknown error!\n" + e, "Error!", JOptionPane.WARNING_MESSAGE);
}
}
}