问一道C++ primer课后习题

习题4.35，不多说了，直接贴代码：

int main()
{
vector<string> svec;
string str;

while(cin>>str)
{
svec.push_back(str);
}

for(vector<string>::iterator itr = svec.begin(); itr != svec.end(); itr++)
{
cout<<*itr<<endl;
}

char **ptr = new char *[svec.size()];

char **p = ptr;

for(itr = svec.begin(); itr != svec.end(); itr++, p++)
{
*p = new char[(*itr).size() + 1];

strcpy(*p,(*itr).c_str());
}

for(vector<string>::size_type ix = 0, p = ptr; ix < svec.size(); ix++, p++)
{
cout<<*p<<endl;
}

return 0;
}

编译后最后的输出语句出错：
D:\test.cpp(64) : error C2040: 'p' : 'unsigned int' differs in levels of indirection from 'char ** '
D:\test.cpp(64) : error C2440: 'initializing' : cannot convert from 'char ** ' to 'unsigned int'

为什么？