Basic Recursion Programs

1.Sum of Digits Example: 123 → 1 + 2 + 3 = 6 --> add all digits of a number Formula sum(n) = (n % 10) + sum(n / 10) java public class Main { static int sumDigits ( int n ) { if ( n == 0 ) return 0 ; return ( n % 10 ) + sumDigits ( n / 10 ); } public static void main ( String [] args ) { System . out . println ( sumDigits ( 123 )); } } python def sum_digits ( n ): if n == 0 : return 0 return ( n % 10 ) + sum_digits ( n // 10 ) print ( sum_digits ( 123 )) javascript function sumDigits ( n ) { if ( n === 0 ) return 0 ; return ( n % 10 ) + sumDigits ( Math . floor ( n / 10 )); } console . log ( sumDigits ( 123 )); output 2.Count Digits in a Number Example: 12345 → 5 digits --> find how many digits are in a number Formula count(n) = 1 + count(n / 10) Java public class Main { static int countDigits ( int n ) { if ( n == 0 ) return 0 ; return 1 + countDigits ( n / 10 ); } public static void main ( String [] args ) { System . out . println ( countDigits ( 12345 )); } } python def count_digits