C++的一个string指针有关问题

C++的一个string指针问题
初学C++，看C++ primer中的一道习题

C/C++ code

#include <iostream>#include <string>#include <vector>using std::string;using std::cin;using std::cout;using std::endl;using std::vector;int main(){   vector<string*> spvec;   string str;      while (cin >> str)   {       string *pstr = new string();       *pstr = str;       spvec.push_back(pstr);   }   vector<string*>::iterator iter = spvec.begin();   while (iter != spvec.end())   {       cout << **iter << " and the length of string is " << (*iter)->size()           << endl;       ++iter;   }   return 0;}