What is the << operator for in C++?

Question

I come from a C# and Java background into C++ and I\'m trying to get to understand the >> & << operators such as in

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Answer 1

<< is the left-shift operator, and >> is the right-shift operator, just as they are in Java and C#.

However, additionally, << is overloaded to provide a way of outputting values to a stream. The stream std::cout usually refers to the terminal the program was launched in, and writing something to that stream with << will write it to the terminal. >> is similarly overloaded to read from streams, and in the case of the stream std::cin to read from the terminal the program was launched on.

This kind of thing works in C++ because you define the behaviour of operators for user-defined types. In java, operators operate only on built-in types - writing a + b is an error if a and b are instances of your own class. In C++, this is allowed if the class defines a suitable operator +.