$($Sum the digits in an integer using recursion$)$

Write a recursive function that computes the sum of the digits in an integer. Use the following method header:

public static int sumDigits$($long n$)$

For example, sumDigits$(234)$ returns $2+3+4=9.$ Write a test program that prompts the user to enter an integer and displays its sum.

Sample Run

Enter an integer: $1231879$

The sum of digits in $1231879$ is $31$