What is really input is the character '7'. All stream operations are done as characters.

> it
> will read the char '7'.

Yes.

> However, char's are really integer types,

Type 'char' is one of the integer types, yes.

> so
> is it possible to set a flag so that you can input an integer that
> will fit in the range of a char (say 100)?

You can ask that a stream convert a sequence of input digit characters to an integer; use the proper overload:

int i; std::cin >> i;

You can determine whether this integer object's value is within type 'char's range:

if(i >= std::numeric_limits::min() && i <= std::numeric_limits::max()) ; /* in range of type 'char' */

> I don't think so, but just
> checking.

If you describe more specifically what you're trying to do, perhaps we can offer better advice.

-Mike