In pre-standard C++, the strstream family of classes was used as buffered stream classes. These classes are now considered deprecated; you should use the stringstream family of classes instead. For example, the following code that uses the deprecated ostrstream class:
ostrstream s; // deprecatedfloat f = 6.6777;s<
should be rewritten as follows:
std::ostringstream s;float f = 6.6777;s<
The ostringstream class returns a string object rather than char *. In addition, it's declared in namespace std. As a rule, use istringstream and ostringstream instead of the deprecated istrstream and ostrstream classes.