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Improved error messages

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Norbi Peti 2016-07-20 09:55:24 +02:00
parent fd2d489480
commit 83e92859aa
2 changed files with 17 additions and 14 deletions
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12
src/calculator/Calc.java
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@ -14,18 +14,14 @@ public class Calc {
private static final Pattern PARENTHESIS = Pattern.compile("\\(([^()]+)\\)"); private static final Pattern PARENTHESIS = Pattern.compile("\\(([^()]+)\\)");
public static Double calculate(String text) { public static String calculate(String text) {
StringBuffer buf = new StringBuffer(text); StringBuffer buf = new StringBuffer(text);
replace(buf, PARENTHESIS, (a) -> calculate(a)); replace(buf, PARENTHESIS, (a) -> calculate(a));
replace(buf, MULTIPLY, (a, b) -> a * b); replace(buf, MULTIPLY, (a, b) -> a * b);
replace(buf, DIVIDE, (a, b) -> a / b); replace(buf, DIVIDE, (a, b) -> a / b);
replace(buf, ADD, (a, b) -> a + b); replace(buf, ADD, (a, b) -> a + b);
replace(buf, SUBTRACT, (a, b) -> a - b); replace(buf, SUBTRACT, (a, b) -> a - b);
try { return buf.toString();
return Double.parseDouble(buf.toString());
} catch (Exception e) {
return null;
}
} }
private static void replace(StringBuffer buf, Pattern pattern, BiFunction<Double, Double, Double> doit) { private static void replace(StringBuffer buf, Pattern pattern, BiFunction<Double, Double, Double> doit) {
@ -38,12 +34,12 @@ public class Calc {
} }
} }
private static void replace(StringBuffer buf, Pattern pattern, Function<String, Double> doit) { private static void replace(StringBuffer buf, Pattern pattern, Function<String, String> doit) {
while (true) { while (true) {
Matcher matcher = pattern.matcher(buf.toString()); Matcher matcher = pattern.matcher(buf.toString());
if (!matcher.find()) if (!matcher.find())
break; break;
buf.replace(matcher.start(), matcher.end(), Double.toString(doit.apply(matcher.group(1)))); buf.replace(matcher.start(), matcher.end(), doit.apply(matcher.group(1)));
} }
} }
} }

19
src/calculator/Gui.java
View file

@ -118,13 +118,20 @@ public class Gui {
tf.setText("0.0"); tf.setText("0.0");
return; return;
} }
Double ret = Calc.calculate(tf.getText()); String result = Calc.calculate(tf.getText());
if (ret == null) String errormsg = "Unbalanced parenthesis: ";
JOptionPane.showMessageDialog(frame, int openc = result.length() - result.replace("(", "").length();
"Unable to convert result to number!\nThis is usually caused by a mistype, like \"5++5\"", int closec = result.length() - result.replace(")", "").length();
"Error!", JOptionPane.WARNING_MESSAGE); if (openc - closec > 0)
errormsg += "There is " + (openc - closec) + " more of ( than )";
else if (openc - closec < 0) {
errormsg += "There is " + (closec - openc) + " more of ) than (";
} else
errormsg = "";
if (errormsg.length() == 0)
tf.setText(Double.toString(Double.parseDouble(result)));
else else
tf.setText(Double.toString(ret)); JOptionPane.showMessageDialog(frame, errormsg, "Error!", JOptionPane.WARNING_MESSAGE);
} catch (ArithmeticException e) { } catch (ArithmeticException e) {
JOptionPane.showMessageDialog(frame, "Arithmetic error: " + e.getMessage(), "Error!", JOptionPane.showMessageDialog(frame, "Arithmetic error: " + e.getMessage(), "Error!",
JOptionPane.WARNING_MESSAGE); JOptionPane.WARNING_MESSAGE);