| ||Little Johnny is in the first grade and just found out about addition. He quickly learned the addition table and is becoming bored in class, so he thinks of a game. The game consists of choosing an integer and summing its digits. If the result is a single digit, the game ends. Otherwise, Johnny repeats the process on the result until he gets a single digit.
For example, if Johnny starts with the number 12345, he will add the digits 1 + 2 + 3 + 4 + 5 to get 15. The result is not a single digit, so he will repeat the process to get 1 + 5 = 6. The new result is a single digit, so the game ends.
Johnny is curious to see if his computations are correct, so he asks you what the final result is for the number n.
|Method signature:||int lastDigit(int n)|
|(be sure your method is public)|
|-||n will be between 0 and 2147483647, inclusive.|
|The example in the problem statement.|
|In this simple example, the sum of the digits is 6, so the game ends after just one step.|
|The sum of the digits is 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 = 81. The process is repeated once more to get 8 + 1 = 9, which is a single digit.|