ostrstream::ostrstream

ostrstream();
ostrstream(char *s, streamsize n,
    ios_base::openmode mode = ios_base::out);

Both constructors initialize the base class by calling ostream(sb), where sb is the stored object of class strstreambuf. The first constructor also initializes sb by calling strstreambuf(). The second constructor initializes the base class one of two ways:

• If mode & ios_base::app == 0, then s must designate the first element of an array of n elements, and the constructor calls strstreambuf(s, n, s).
• Otherwise, s must designate the first element of an array of n elements that contains a C string whose first element is designated by s, and the constructor calls strstreambuf(s, n, s + strlen(s).