Parametrized stream manipulator

[rwawryk]

Hi,

Does anybody know how to implement parametrized stream operator (such as
setw, setfill)? I need to put into the stream variable of type char* without
terminating NULL. It would be great if I had the manipulator which allows to
determine maximum number of characters ( let's assume maxw( char* str, int
maxlen ) ).

example:
cout << maxw("Crocodile", 5 );
Croco

thanx in advance
ralfer

ps. prefer templates to macros...

 

[Victor Bazarov]

Does anybody know how to implement parametrized stream operator (such as
setw, setfill)? I need to put into the stream variable of type char* without
terminating NULL. It would be great if I had the manipulator which allows to
determine maximum number of characters ( let's assume maxw( char* str, int
maxlen ) ).

example:
cout << maxw("Crocodile", 5 );
Croco

thanx in advance
ralfer

ps. prefer templates to macros...

(a) If you need to put several chars into the stream, just put
them into the stream. No "terminating NULL" is copied into the
stream. cout << string("Crocodile").substr(5); should do it.

(b) Usually parameterised manipulators are written either as
functions that return special objects or just as classes [that
you construct right there], which, when output to a stream, do
something to the stream:

struct maxw {
maxw(const char*, int); // constructor
ostream& print(ostream&) const; // output
// some data
};

ostream& operator <<(ostream& os, const maxw& m) {
return m.print(os);
}

maxw::maxw(const char* s, int n) : ....

ostream& maxw:rint(ostream& os) const {
// do something to the stream to output what you need
// in a special way
}

HTH

Victor

 

[Shane Beasley]

(a) If you need to put several chars into the stream, just put
them into the stream. No "terminating NULL" is copied into the
stream. cout << string("Crocodile").substr(5); should do it.

That's "odile". You meant string("Crocodile").substr(0, 5).

- Shane

 

[Victor Bazarov]

"Victor Bazarov" <[email protected]> wrote in message

That's "odile". You meant string("Crocodile").substr(0, 5).

Right. Should have probably said

string("Crocodile", 5)

(without substr).

Victor