Stefan Freitag February 2016
If I read your code and the stack trace right, I can assume that the method
mobile_number is called with a string that has at least 10 characters. This line is doing so:
There are no assumptions about the maximum lenght of the string. You try to access separate character of the string like
but never check if the position (i.e.
i+11) is pointing to a character within your string. For some positions this may hold, but for others you will receive the mentioned