PAT Basic 1002 写出这个数 (20 分)

#include<iostream>
#include<stack>
using namespace std;
int main() {
    string s;
    int sum=0;
    stack<int> sta;
    cin>>s;
    for(int i=0;i<s.length();i++){
        sum+=(s[i]-‘0‘);
    }
    while(sum!=0){
        sta.push(sum%10);
        sum/=10;
    }
    while(!sta.empty()){
        switch(sta.top()){
            case 1:cout<<"yi";break;
            case 2:cout<<"er";break;
            case 3:cout<<"san";break;
            case 4:cout<<"si";break;
            case 5:cout<<"wu";break;
            case 6:cout<<"liu";break;
            case 7:cout<<"qi";break;
            case 8:cout<<"ba";break;
            case 9:cout<<"jiu";break;
            case 0:cout<<"ling";break;
        }
        if(sta.size()!=1) cout<<" ";
        sta.pop();
    }
    system("pause");
    return 0;
}