Check if a number is divisible by 23 or not in C++

Here we will see one program, that can check whether a number is divisible by 23 or not. Suppose a number 1191216 is given. This is divisible by 23.

To check the divisibility, we have to follow this rule −

• Extract the last digit of the number/truncated number every time

• add 7 * (last digit of the number calculated previous) to the truncated number

• Repeat these steps as long as necessary.

17043, so 1704 + 7*3 = 1725 1725, so 172 + 7 * 5 = 207 207, this is 9 * 23, so 17043 is divisible by 23.

Example

 Live Demo

#include <iostream> #include <algorithm> using namespace std; bool isDivisibleBy23(long long int n) {    while (n / 100) {       int last = n % 10;       n /= 10; // Truncating the number       n += last * 7;    }    return (n % 23 == 0); } int main() {    long long number = 1191216;    if(isDivisibleBy23(number))       cout << "Divisible";    else       cout << "Not Divisible"; }

Output

Divisible