3 AnswersNew Answer
vineet The iostream is the standard C++ library for streaming input and output. Just similar to or inherited from stdio in C which defines standard input output library functions in ANSI/standard C. iostream header<iostream.h> file is declared along with the preprocessor directive of #include which is responsible for telling the compiler to include the standard C++ library of iostream before compiling the program.So it is processed by the preprocessor to include the iostream.h header file before compiler compiles the program and required by the compiler to compile the program for cout,cin. iostream defines all the standard library streams like cin,cout,clog,cerr. iostream is used so as to facilitate the input and output services like that of cin and cout and others. Preprocessor directive #include tells the compiler to compile the program including the <iostream.h> header file.So as to read cin and cout without any compilation errors.And so during runtime you are able to give/recieve input/output through/from the I/O console(like keyboard and monitor) which streams the i/o through buffering. So we need to write, #include<iostream.h> Hope clarified ☺️.
iostream is basically a header file which contain all the declaration of functions.