Left shift

Question

This just came to my mind, is << which comes after cout, the left shift operand? If so... Why! How does this end in printing?

Answer 1

They're based on UNIX redirection commands <, <<, > and >>
where > overwrites a file, >> appends to a file,
< takes input from a file and << used for appended input.

A common usage of redirection is when using cat on a unix-like system to append text to a file until you reach a delimiter like $ or EOF:

cat >> myfile << EOF
line of text . . .
EOF

In the context of cout they're not bitshifts but stream redirections, so if you want to print the result of a left/right bitshift using cout you have to parenthesize the expression.