Standard library header <iostream>
From cppreference.com
                    
                                        
                    
                    
                                                            
                    This header is part of the Input/output library.
| Includes | |
| <ios> | (since C++11) | 
| <streambuf> | (since C++11) | 
| <istream> | (since C++11) | 
| <ostream> | (since C++11) | 
| Objects | |
| std::cin | standard input | 
| std::cout | standard output | 
| std::cerr | standard error | 
| std::clog | standard log | 
| std::wcin | standard input | 
| std::wcout | standard output | 
| std::wcerr | standard error | 
| std::wclog | standard log | 
[edit] Synopsis
#include <ios> #include <streambuf> #include <istream> #include <ostream> namespace std { extern istream cin; extern ostream cout; extern ostream cerr; extern ostream clog; extern wistream wcin; extern wostream wcout; extern wostream wcerr; extern wostream wclog; }