Andy's First Dictionary（uva 10815） set用法

参考：https://www.cnblogs.com/yjlblog/p/6947747.html

https://blog.csdn.net/hnust_taoshiqian/article/details/43448793

https://blog.csdn.net/liuke19950717/article/details/49450817

https://blog.csdn.net/fanyun_01/article/details/66967710

 #include <iostream>
 #include <cstdio>
 #include <set>
 #include <sstream>
 using namespace std;
 set<string> ans;
 int main()
 {
     string s,temp;
 //    freopen("总结.txt","r",stdin);
     while (cin>>s)//cin遇空格结束 ~
     {
         int i;
         for (i=;i<s.length();i++)
         {
             if (isalpha(s[i]))
             {
                 s[i]=tolower(s[i]);
             }
             else
             {
                 s[i]=' ';
             }
         }
         stringstream ss(s);//ss流初始化
         while (ss>>temp)//同一个cin进来的s可能有多个单词~
         {
             ans.insert(temp);
         }
     }
     set<string>::iterator it;
     for (it=ans.begin();it!=ans.end();it++)
     {
         cout<<*it<<endl;
     }

     return ;
  }