Explain please

Question

look some blogs are saying that..... cout cin these objects are defined in iostream header files.. ...some are saying they are defined in istream and ostream...... and some are saying they are defined in namespace....... where these are actually defined and how namespace std actually works....

Answer 1

cin is object of class istream. cout is object of class ostream. These objects and their classes defined in std namespace in iostream

Answer 2

Why don't you look at them yourself?

GNU's iostream: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/include/std/iostream

GNU's istream:
https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/include/std/istream

GNU's ostream: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/include/std/ostream