华为OJ：字符串处理

 #include <iostream>
 #include <stdlib.h>
 #include <string>
 #include <sstream>
 #include <vector>
 using namespace std;

 int main()
 {
     string s;
     getline(cin, s);
     for (auto it = s.begin(); it != s.end(); it++)
     {
         if (!isalpha(*it))
             (*it) = ' ';
     }

     istringstream ss(s);
     string tmp;
     vector<string>ans;
     while (ss>>tmp)
     {
         tmp[] = toupper(tmp[]);
         ans.push_back(tmp);
         //tmp.clear();
     }
     (ans.back()).insert((ans.back()).end(), '.');
     for (auto it = ans.begin(); it != ans.end(); it++)
     {
         if (it == prev(ans.end()))
             cout << *it;
         else
             cout << *it << ' ';
     }
     system("pause");
     return ;
 }