what is iostream and what is it used for
it is a class defined in the header file iostream.h or iostream this class (input output stream) can control the output screen in the console that you see as output (in pc) it has four objects through which you do stuff cout cin cerr clog first two are necessary but if you wanna go in detail then refer http://www.cplusplus.com/reference/iostream/
input output stream
thank you very much for your answer
iostream is a header file used in c++
it's a header file with is use for input and output and also called as pre processor file.