c++ stringstream

greg108 · 06-23-2005, 04:31 PM

How can I flush stringstream?

bigfez · 06-23-2005, 04:53 PM

Code:

stringstream mystringstream;
mystringstream.flush();

you can also just put an endline into the stream too.

Code:

stringstream mystringstream;
string mymessage;
mystringstream << mymessage << endl;

the endl will flush the stream too.

greg108 · 06-23-2005, 04:59 PM

Well, I tried both even before and it didn't work. Am I missing something else.
I'm trying to do something like that:

Code:

    std::stringstream my_stringstream;
    my_stringstream <<  struct_map->getObject(row, col)->numOccupants();
    switch(i)
      {
      case VILLAGE :
	str = "Village\nOccupants: ";
	str += my_stringstream.str();
	str += "\nRecruits: ";
	my_stringstream.flush();
	my_stringstream <<  struct_map->getObject(row, col)->numRecruits();
	str += my_stringstream.str();
	break;

bigfez · 06-23-2005, 05:06 PM

if you are looking for output to stdout you may want to use an ostringstream instead.

I've never used just stringstream but i believe it is used for loading a string buffer.

<edit> never mind, i just read your code more closely</edit>

greg108 · 06-23-2005, 05:15 PM

What would be the best way to change int to string?

carl.waldbieser · 06-23-2005, 11:28 PM

This might more easily accomplish what you want to do. String streams are great for pasting together strings (like embedded SQL statements, for example).

Code:

    
    std::stringstream my_stringstream;
    switch(i)
      {
      case VILLAGE :
        my_stringstream.str("");
	my_stringstream 
           << "Village\nOccupants: "
           << struct_map->getObject(row, col)->numOccupants()
	   << "\nRecruits: "
	   <<  struct_map->getObject(row, col)->numRecruits();
        std::cout << myStringStream.str();
	break;

greg108 · 06-24-2005, 01:44 AM

Thanks carl.waldbieser,
I guess I haven't worked enough with streams to figure out that it's so simple.

dakensta · 06-24-2005, 07:48 AM

Possibly worth noting that flush() is used to flush the underlying buffer to the associated device.

Consider a file stream : you would flush() the contents to the file on disk, emptying the internal filebuf.

With a stringstream you are flush() the contents to the string in memory, emptying the internal stringbuf. In all likelihood the internal stringbuf writes directly to this string, effecively making the "buffer" and "device" the same.

Hence, flush() on stringstream doesn't work as you might expect (emptying the underlying string).