What is the difference between cout, cerr, clog of iostream header in c++? When to use which one?

Question

I tried researching the difference between cout, cerr and clog on the internet but couldn't find a perfect answer. I still am not clear on when to use which. Can anyone explain to me, through simple programs and illustrate a perfect situation on when to use which one?

I visited this site which shows a small program on cerr and clog, but the output obtained over there can also be obtained using cout. So, I'm confused over each one's exact use.

Answer 1

Generally you use std::cout for normal output, std::cerr for errors, and std::clog for "logging" (which can mean whatever you want it to mean).

The major difference is that std::cerr is not buffered like the other two.

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In relation to the old C stdout and stderr, std::cout corresponds to stdout, while std::cerr and std::clog both corresponds to stderr (except that std::clog is buffered).