The difference between "C + +" cout, Cerr, clog

cout, Cerr, and clog are the output tools available in the standard IO library.

However, cout is supported for redirection operations . For example , freopen () is valid for cout.
Clog and Cerr are primarily used for error outputs.
Therefore, if you redirect the program output to a file and an error occurs, the error message still appears on the screen.

Official Note: Https://zh.cppreference.com/w/cpp/io

defined in the header file <iostream>
Cin	Read from standard C input stream stdin
cout	Write to standard C output stream stdout
Cerr	Write standard C error stream stderr, unbuffered
Clog	Write standard C error stream stderr

The difference between "C + +" cout, Cerr, clog