Java NumberFormatException while converting 1000000000000001 to base 5

Question

I am trying to convert the String "1000000000000001" to base 5 using Java:

Integer number = Integer.parseInt("1000000000000001", 5);

However, I am gettig NumberFormatException. The string is trimmed and only contains 1 and 0. Could someone please explain why am I getting this exception?

Answer 1

The number 1000000000000001 in base 5 is equivalent to the number 30517578126 in base 10 (you can verify this yourself or use online tools).

However, 30,517,578,126 is too big to fit in an int value. The maximal value, Integer.MAX_VALUE is 2,147,483,647. This explains the exception you are getting - from parseInt:

throws NumberFormatException - if the String does not contain a parsable int.

which is the case here.

You need to use a long:

public static void main(String[] args) {
    long number = Long.parseLong("1000000000000001", 5);
    System.out.println(number); // prints "30517578126"
}