Format money for a receipt
The receipt printer takes a plain string. Amounts arrive in minor units and have to come out grouped and signed the way finance expects.
- Always two decimal places.
- Group the whole part in threes with commas: 123456 becomes 1,234.56.
- Negatives are wrapped in parentheses with no minus sign, so -50 becomes (0.50).
formatMoney(minor: int) → string
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
String formatMoney(int minor) {
}Worked examples
| Call | Result |
|---|---|
formatMoney(123456) | "1,234.56" |
formatMoney(0) | "0.00" |
formatMoney(5) | "0.05" |
formatMoney(-50) | "(0.50)" |
Hint
Split into whole and remainder first, build the grouped whole part, then glue on the sign.
Reference solution in Java
String formatMoney(int minor) {
boolean neg = minor < 0;
int abs = Math.abs(minor);
String whole = String.valueOf(abs / 100);
String cents = String.valueOf(abs % 100);
if (cents.length() < 2) cents = "0" + cents;
StringBuilder g = new StringBuilder();
for (int i = 0; i < whole.length(); i++) {
if (i > 0 && (whole.length() - i) % 3 == 0) g.append(',');
g.append(whole.charAt(i));
}
String body = g + "." + cents;
return neg ? "(" + body + ")" : body;
}