[lug] simple iostream bug?

Fri Mar 15 01:23:49 MST 2002

Tkil wrote:
> 
> >>>>> "DS" == D Stimits <stimits at idcomm.com> writes:
> 
> DS> Basically it is just a function to take a reference to an ostream,
> DS> insert some text, and return it by reference. In this case it is
> DS> cout.
> 
> a more c++ish idiom (at least to my eyes) would be to create an
> object, and then print the object (using "<<") onto the output stream.

I thought about this, and might still do it, but I considered it
unneeded overhead for the moment (hit based application, it would need a
construct and destruct for every web page hit). This seemed "lighter
weight" for the moment (I don't expect a lot of hits, so it might be
irrelevant).

D. Stimits, stimits at idcomm.com

> 
> there's a nice idiom for making "<<" behave polymorphically, as well:
> 
> | #include <iostream>
> | using std::cout;
> |
> | #include <iomanip>
> | using std::endl;
> |
> | #include <string>
> | using std::string;
> |
> | class HTTPHeader {
> | private:
> |     int    status_code_;
> |     string content_type_;
> | public:
> |     HTTPHeader(int status_code,
> |                const string & content_type)
> |       : status_code_(status_code),
> |         content_type_(content_type)
> |     {}
> |
> |     virtual ostream & print_to_ostream(ostream & os) const;
> |     static string status_text(int status_code);
> | };
> |
> | ostream &
> | HTTPHeader::print_to_ostream(ostream & os) const
> | {
> |     return os << status_code_ << " " << status_text(status_code_) << endl
> |               << "Content-type: " << content_type_ << endl;
> | }
> |
> | string
> | HTTPHeader::status_text(int status_code)
> | {
> |     switch (status_code)
> |     {
> |     case 200: return "Ok";
> |     default:  return "Unknown Status";
> |     }
> | }
> |
> | ostream &
> | operator << (ostream & os, const HTTPHeader & h)
> | {
> |     return h.print_to_ostream(os);
> | }
> |
> | int main(int argc, char * argv [])
> | {
> |     HTTPHeader header(200, "text/html");
> |
> |     cout << header << endl
> |          << "<html>" << endl
> |          << "  <head><title>test</title</head>" << endl
> |          << "  <body><p>foo</p</body>" << endl
> |          << "</html>" << endl;
> |
> |     return 0;
> | }
> 
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