Check if a large number is divisible by 8 or not in C++

Here we will see how to check a number is divisible by 8 or not. In this case the number is very large number. So we put the number as string.

A number will be divisible by 8, if the number formed by last three digits are divisible by 8.

Example

#include <bits/stdc++.h>
using namespace std;
bool isDiv8(string num){
   int n = num.length();
   int last_three_digit_val = (num[n-3] - '0') * 100 + (num[n-2] - '0') * 10 + ((num[n-1] - '0'));
   if(last_three_digit_val % 8 == 0)
      return true;
      return false;
}
int main() {
   string num = "1754586672360";
   if(isDiv8(num)){
      cout << "Divisible";
   }else{
      cout << "Not Divisible";
   }
}

Output

Divisible