In C++, I would like to initialize a vector of sets of strings by:

```
string border(getBorder());
vector<string> W(_h_,border+"_"+border);
vector< set<string> > W_f(_h_,getNgrams(&W[0]));

```

where:

```
set<string> getNgrams(string word){ ... }

```

and:

```
string getBorder(){ ... }

```

The error message reads:

```
conversion from 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >*' to non-scalar type 'std::string' requested

```