The digital root of a positive integer is found by summing the digits of the integer. If the resulting value is a single digit then that digit is the digital root. If the resulting value contains two or more digits, those digits are summed and the process is repeated. This is continued as long as necessary to obtain a single digit.
Given a large number N, the task is to find its digital root. The input number may be large and it may not be possible to store even if we use long long int.
Input: N = 675987890789756545689070986776987
Sum of individual digit of the above number = 212
Sum of individual digit of 212 = 5
So the Digital root is 5
Input: num = 876598758938317432685778263
Sum of individual digit of the above number = 155
Sum of individual digit of 155 = 11
Sum of individual digit of 11 = 2
So the Digital root is 2
- Find out all the digits of a number
- Add all the number one by one
- If the final sum contains more than one digit, Call the recursive function again to make it single digit
- The result obtained in single digit is the Digital root of number
Below is the implementation of the above approach:
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