初学者对地址分配的提问

#include "iostream"
#include "cstring"
#include "string"
using namespace std;
string* getname();

int main()
{
string* name;
name=getname();
cout << *name << " at " << name << endl;
delete []name;
name=getname();
cout << *name << " at " << name << endl;
delete []name;
return 0;
}

string* getname()
{
string temp;
cout << "Enter your last name: ";
cin >> temp;
string* pn = new string[temp.size()+1];
//为什么去掉temp.size()+1会出错？
*pn = temp;
return pn;
}
//为什么两次地址都相同？

 #include "iostream"
#include "cstring"
#include "string"
using namespace std;
string* getname();
int main()
{
    string* name;
    name=getname();
    cout << *name << " at " << name << endl;
    delete name;
    name = NULL;

    name=getname();
    cout << *name << " at " << name << endl;
    delete name;
    name = NULL;
    return 0;
}
string* getname()
{
    string temp;
    cout << "Enter your last name: ";
    cin >> temp;
    string* pn = new string;
    *pn = temp;
    return pn;
}