Prevents security issues when the string contains
format specifiers.
Fixes: warning: format not a string literal and
no format arguments [-Wformat-security]
- using std::string;
- using std::wstring;
- using std::ostream;
- using std::istream;
- using std::iostream;
- using std::ostrstream;
- using std::istrstream;
- using std::fstream;