Check Divisibility by 3 Using Array Digits in C++

In this section we will see if one array is given with n numbers, we have to check if we make a number using all of the elements of these numbers, that number will be divisible by 3 or not. If the array elements are {15, 24, 23, 13}, then the we can make integer like 15242313. It will be divisible by 3.

Algorithm

checkDivThree(arr)

Begin
   rem := 0
   for each element e in arr, do
      rem := (rem + e) mod 3
   done
   if rem is 0, then
      return true
   end if
   return false
End

Example

#include<iostream>
#define MAX 4
using namespace std;
bool checkDivThree(int arr[], int n){
   int rem = 0;
   for(int i = 0; i<n; i++){
      rem = (rem + arr[i]) % 3;
   }
   if(rem == 0){
      return true;
   }
   return false;
}
main() {
   int arr[] = {15, 24, 23, 13};
   int n = sizeof(arr)/sizeof(arr[0]);
   if(checkDivThree(arr, n)){
      cout << "Divisible";
   }else{
      cout << "Not Divisible";
   }
}

Output

Divisible