leetcode1281 整数的各位积和之差

class Solution {
public:
    int subtractProductAndSum(int n) {
        int add=; int prod=;
        while(n>){
            int r=n%;
            n/=;
            prod*=r;
            add+=r;
        }
        int res=prod-add;
        return res;
    }
};