Trouble with strstream

I'm trying to get strstream to work and its not working right. Both these code output stuff to a string except that it doesn't put a null so the output just keeps going until a zero. I'm using unmanaged VC.NET.

Code:

char buffer[1024];
ostrstream s(buffer, sizeof(buffer);
s << "hey" << uppercase << hex << 255 << endl;

// will work with this here, but it should even without:
// str[s.pcount()]=0;

cout << s.str();

Code:

strstream s;
s << "hey" << uppercase << hex << 255 << endl;
cout << s.str();

Output of both codes (nothing else is printed):

Code:

heyFF
══════════════════════════²²²²½½½½½½½½ε■ε■

Nevermind, I found the solution. To end a string stream, you must place a ends at the end (end string). That way the string will be terminated by a zero. So this works:

Code:

ostrstream s;
s << "hey" << uppercase << hex << 255 << ends;
cout << s.str();

<posting because someone might wanna search this topic later>