These methods write on an ostream (you may also use the operator <<; see Operators and Default Streams.).
ostream& ostream::put (char c) Method
Write the single character c.
ostream& ostream::write (string, int length) Method
Write length characters of a string to this ostream, beginning at the pointer, string. string may have any of these types: char*, unsigned char*, signed char*.
ostream& ostream::form (const char *format, ...) Method
A GNU extension, similar to fprintf (file, format, ...).
94cformat is a printf-style format control string, which is used to format the (variable number of) arguments, printing the result on this ostream. See ostream::vform for a version that uses an argument list rather than a variable number of arguments.
ostream& ostream::vform (const char format, va_list args) Method
A GNU extension, similar to vfprintf(file, format, args).format is a printf-style format control string, which is used to format the argument list args, printing the result on this ostream. See ostream::form, previously, for a version that uses a variable number of arguments rather than an argument list.