Hanks Homework,

[hankofwisdom]

Are we going to learn Pointers math
Why dose auto on an iostream make it an integer?

[froschs]

You can put using std::cin; and using std::cout; up here and then just write cin and cout below.

[ninjapanzer]

@hankofwisdom what was an example of a statement where you were using auto with ifstream?

[hankofwisdom]

@ninjapanzer it was the top comment I read the iostream class and it won't work

[ninjapanzer]

cin is declared as as iostream and then applied to tie to bind it to the std stream. But I will have to try it later.

[ninjapanzer]

So the reality is that C++ also includes a move constructor because streams like CIN cannot be copied. Move rebinds the internal std::Tie class to the new stream object.

But it turns out there is a defect in how basic_streams are handled.
http://cplusplus.github.io/LWG/lwg-defects.html#911
From response http://stackoverflow.com/a/20774666

That said by using = implies a copy constructor due to operator overloading. You might be used to languages that hide references and pointers behind variable names. Anything that is not a primitive is actually a reference so when you do Object<thing1> var1 = var2; You are actually manipulating the reference of var1 instead of duplicating it. So here is an example of how a pointer could be employed to create an "alias" of the original variable. And auto does nothing but infer the type so these two statements are equivalent.

auto ins = std::cin;
istream ins = std::cin;

Both try to invoke the disabled copy constructor and thus fail because you can't copy a stream. Of course they provide a move method that is also basically disabled due to defect.

Pointers do simplify this and here is an example of basically what every other pointer abstracting language does https://gist.github.com/ninjapanzer/aa9cdd6f0d6a34d1f0df

[ninjapanzer]

Dangerous global variables that are not const could lead to data side-effects an difficult debugging. These should be within you main function or const.