Why are bitwise shifts (<< and>>) used for cout and cin?

Question

Question is in the title really; I\'m sure there is something logical, but for now I\'m stumped!

Answer 1

I assume that you are aware that C++ allows for operator overloading. In general, you overload operators only if the semantics are completely transferable (e.g. overloading the addition for a vector class to add two vectors together). I think your question refers to why one would use bitshift operators, overload them for the iostream, and give them a completely different meaning than their original purpose. The reason it can be done is because bitshift operations are so far removed from what iostreams do that no one could be confused into thinking that << or >> is doing a bitshift on an iostream. And the reason why they are convenient to use also is that their ordering is to evaluate the operand on the left first, then the one on the right, and do the operation. This fits to what you would want to happen when you are using the operators to append or extract stuff from an iostream.

But, to the original question, why? I don't really know, it just seems to me like the << and >> are pretty easily understood as taking information from one entity and putting it in the other. Why does the reason need to be more complicated than that? It looks sensible to use those because their meaning is obvious.. what better could you ask of an operator?