Question

Write c++ recursive function

3. A function that takes an integer, and returns the product of the digits, so the input 1989 would return 1∗9∗8∗9 = 648

4. A function that does the above repeatedly, taking a number and computing the product

of it’s digits until you get a single digit number: so on input 1989 it would go 1989→648→192→18→8 and return 8. (Note, you can use the previous functions if you want.

Answer 1

#include <iostream>

using namespace std;

int product(int n) {
    if (n < 10) {
        return n;
    } else {
        return (n % 10) * product(n / 10);
    }
}

int product_digit(int n) {
    if (n < 10) {
        return n;
    } else {
        return product_digit(product(n));
    }
}

int main() {
    cout << product(1989) << endl;
    cout << product_digit(1989) << endl;
    return 0;
}