Problem:

Given an integer, find the number of digits in it.

Example:

Input: 1234
Output: 4
Input: -789435
Output: 6

Approach 1) Iterative

Every time we divide a number by 10, the number of digits reduces by 1. So, we can count it until the number becomes 0.

public class Solution {
    int countDigits(int n){
        int ans = 0;
        while(n!=0){
            n/=10;
            ans++;
        }
        return ans;
    }
    public static void main(String[] args){
        int num = 12345;
        System.out.println(countDigits(num));
    }
}

• Time complexity: O(number of digits)

• Space complexity: O(1)