sting迭代器的使用

buptoj 1512

#include 
#include 
using namespace std;

int main(int argc, char *argv[])
{
    string num;
    num.clear();

    cin >> num;
    string::iterator iter; /* how to using string iterator */

    int nine = 0, one = 0, two = 0;
    for (iter=num.begin() ; iter!=num.end() ; iter++)
    {
        if (*iter == '9')
        {
            nine++;
        }
        else if (*iter == '1')
        {
            one++;
        }
        else if (*iter == '2')
        {
            two++;
        }
    }
    
    cout << nine << endl;
    cout << one << endl;
    cout << two << endl;
}