Given an integer number n, return the difference between the product of its digits and the sum of its digits.
 
Example 1:
Input: n = 234
Output: 15 
Explanation: 
Product of digits = 2 * 3 * 4 = 24 
Sum of digits = 2 + 3 + 4 = 9 
Result = 24 - 9 = 15
Example 2:
Input: n = 4421
Output: 21
Explanation: 
Product of digits = 4 * 4 * 2 * 1 = 32 
Sum of digits = 4 + 4 + 2 + 1 = 11 
Result = 32 - 11 = 21
 
Constraints:
1 <= n <= 10^5
会提取数字就行了。
class SubtractTheProductAndSumOfDigitsOfAnInteger : public Solution {
public:
    void Exec() {
    }
    int subtractProductAndSum(int n) {
        int product = 1, sum = 0;
        while (n > 0) {
            product *= (n % 10);
            sum += (n % 10);
            n /= 10;
        }
        return product - sum;
    }
};
