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c++operatorsostreamassociativity

What do you mean by left to right associativity in this case?

I was reading about the << operator in c++ from C++ Primer.
In it, there are some lines written about << operator

cout << "Some string" evaluates to a left hand ostream operator that is the result of the expression is cout object itself.(We say that operator associates left to right) .

It would be great it someone explains what is the meaning of the above mentioned lines.

Solution

  • Left to right associativity means that the expression is implicitly parenthesized like this:

    (((cout << "foo") << "bar") << "baz")

    In other words, the leftmost operation comes first.

    By contrast, assignment is right-associative in most languages:

    a = b = c + 5;

    assigns c + 5 to both "a" and "b" because the assignment operator works from right-to-left.