Codeforces Beta Round #91 (Div. 2 Only) - A. Lucky Division

problem statement
As you read in the problem statement, you have to find out whether a number has a divisor which is also a lucky number, so iterate from 1 to n, if n is divisible by i, then check whether it is a lucky number or not?
Easily write a function that take a number and tell whether it is lucky or not, in other words the function checks whether all of the digits in the given number are 4 or 7.

1. bool isLucky(int n)
2. {
3.     int rem;
4.     while(n)
5.     {
6.         rem = n%10;
7.         if(rem != 7 && rem != 4)
8.             return false;
9.         n /= 10;
10.     }
11.     return true;
12. }