Given a number n, we need to find the sum of each digits of the number till the number becomes a single digit. We need to print “yes” if the sum is a prime or “no” if it is not prime.
Examples:
Input : 5602 Output: No Explanation: Step 1- 5+6+0+2 = 13 Step 2- 1+3 = 4 4 is not prime Input : 56 Output : Yes Explanation: Step 1- 5+6 = 11 Step 2- 1+1 = 2 hence 2 is prime
The idea is simple, we can quickly find recursive sum of digits.
int recDigSum(int n)
{
if (n == 0)
return 0;
return (n % 9 == 0) ? 9 : (n % 9);
}
Once, recursive sum is calculated, check if it is prime or not by simply checking if it is 2, 3, 5 or 7 (These are only single digit primes).
C++
// CPP code to check if// recursive sum of// digits is prime or not.#include<iostream>using namespace std;// Function for recursive // digit sum int recDigSum(int n){ if (n == 0) return 0; else { if (n % 9 == 0) return 9; else return n % 9; }} // function to check if prime// or not the single digit void check(int n){ // calls function which // returns sum till // single digit n = recDigSum(n); // checking prime if (n == 2 or n == 3 or n == 5 or n == 7) cout << "Yes"; else cout << "No";}// Driver codeint main(){ int n = 5602; check(n);}// This code is contributed by Shreyanshi. |
Java
// java code to check if// recursive sum of// digits is prime or not.import java.io.*;class GFG { // Function for recursive // digit sum static int recDigSum(int n) { if (n == 0) return 0; else { if (n % 9 == 0) return 9; else return n % 9; } } // function to check if prime // or not the single digit static void check(int n) { // calls function which // returns sum till // single digit n = recDigSum(n); // checking prime if (n == 2 || n == 3 || n == 5 || n == 7) System.out.println ( "Yes"); else System.out.println("No"); } // Driver code public static void main (String[] args) { int n = 5602; check(n); }}// This code is contributed by vt_m |
Python
# Python code to check if recursive sum# of digits is prime or not.def recDigSum(n): if n == 0: return 0 else: if n % 9 == 0: return 9 else: return n % 9 # function to check if prime or not# the single digit def check(n): # calls function which returns sum # till single digit n = recDigSum(n) # checking prime if n == 2 or n == 3 or n == 5 or n == 7: print "Yes" else: print "No" # driver code n = 5602check(n) |
C#
// C# code to check if// recursive sum of// digits is prime or not.using System;class GFG { // Function for recursive // digit sum static int recDigSum(int n) { if (n == 0) return 0; else { if (n % 9 == 0) return 9; else return n % 9; } } // function to check if prime // or not the single digit static void check(int n) { // calls function which // returns sum till // single digit n = recDigSum(n); // checking prime if (n == 2 || n == 3 || n == 5 || n == 7) Console.WriteLine ( "Yes"); else Console.WriteLine("No"); } // Driver code public static void Main () { int n = 5602; check(n); }}// This code is contributed by anuj_67. |
PHP
<?php// PHP code to check if// recursive sum of// digits is prime or not.// Function for recursive // digit sum function recDigSum($n){ if ($n == 0) return 0; else { if ($n % 9 == 0) return 9; else return $n % 9; }} // function to check if prime// or not the single digit function check( $n){ // calls function which // returns sum till // single digit $n = recDigSum($n); // checking prime if ($n == 2 or $n == 3 or $n == 5 or $n == 7) echo "Yes"; else echo "No";}// Driver code$n = 5602;check($n);// This code is contributed by ajit.?> |
Javascript
<script>// Javascript code to check if// recursive sum of digits is // prime or not.// Function for recursive // digit sum function recDigSum(n){ if (n == 0) return 0; else { if (n % 9 == 0) return 9; else return n % 9; }} // Function to check if prime// or not the single digit function check(n){ // Calls function which // returns sum till // single digit n = recDigSum(n); // Checking prime if (n == 2 || n == 3 || n == 5 || n == 7) document.write("Yes"); else document.write("No");}// Driver codelet n = 5602;check(n);// This code is contributed by susmitakundugoaldanga</script> |
Output:
No
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