creating a << operator

I have a map <string, vector of ints> and would like to display what I hope I have loaded into the map...however, it appears that I have to define a << operator that takes a type HEADINGMAP (my map type).

Could anyone pls assist.
Thanks
s

This is the best I can do with what little detail you've provided.

Code:

---

ostream& operator<<(ostream& out, const HEADINGMAP& hmap)
{
  // Code to write the contents of hmap to out
  return out;
}

---

Thanks Kip,

I have included your code - but am now getting compile errors...

error C2143: syntax error : missing ',' before '&'

does hmap have to be declared elsewhere - in a .h ?? It says it is undeclared...

I have tried to use:
out << *hmap->first << ": ";

to display the string portion of the map, but am getting a compile error - error C2227: left of '->first' must point to class/struct/union

I need to be able to access the key and values within the map - in order to write them to a report.
Thanks for your help
sue

Quote:

---

Originally Posted by Sue Paterniti

Thanks Kip,

I have included your code - but am now getting compile errors...

error C2143: syntax error : missing ',' before '&'

does hmap have to be declared elsewhere - in a .h ?? It says it is undeclared...

I have tried to use:
out << *hmap->first << ": ";

to display the string portion of the map, but am getting a compile error - error C2227: left of '->first' must point to class/struct/union

I need to be able to access the key and values within the map - in order to write them to a report.
Thanks for your help
sue

---

This has all the signs of HEADINGMAP not being a type. What does the declaration of HEADINGMAP look like? I was under the impression that you were doing something like this.

Code:

---

typedef map< string, vector<int> > HEADINGMAP;

[...]

ostream& operator<<(ostream& out, const HEADINGMAP& hmap)
{
  HEADINGMAP::const_iterator i = hmap.begin();

  for (; i != hmap.end(); ++i) {
    out << i->first << ": ";
  }

  return out;
}

---

Sue,
You need to read up on operator overloading. Then you'll be able to make sense of Kips code and implement it into your code.

Its not a large topic for what you need, and should help you.

hth

Hi Kip,
I have typedef'd an int vector as typedef vector<int> INTVEC;
Then typdef'd the map as typedef map <string, INTVEC > HEADINGMAP;
and an iterator as typedef HEADINGMAP::iterator HEADMAPIT;

am still getting the compile error that there is a missing ',' before a '&' - but will do some more reading as recommended...
thanks
s