Count7.java

/*
Given a non-negative int n, return the count of the occurrences of 7 as a digit, so for example 717 yields 2. (no loops). Note that mod (%) by 10 yields the rightmost digit (126 % 10 is 6), while divide (/) by 10 removes the rightmost digit (126 / 10 is 12).
count7(717) → 2
count7(7) → 1
count7(123) → 0
*/

public int count7(int n) {
  //The logic - Get the remainder at each recursive, if the remainder returns 7, return 1, else 0
  if(n<10 && n%10 == 7) return 1;
  else if(n<10 && n%10 != 7) return 0;
  
  if(n%10 == 7) return 1+count7(n/10);
  return 0+count7(n/10);
}