You can’t return an istream by value because it’s not copyable.
Since it’s not copyable the copy constructor has been deleted (to enforce the non-copyability), and that’s the direct technical cause of the diagnostic.
So, instead of
std::istream ReadFile(std::istream &iStream)
… do
std::istream& ReadFile(std::istream& iStream)
In other news, …
Instead of
#include "stdafx.h"
just turn off precompiled headers in the Visual Studio project settings.
This also gives you more standard-conforming behavior for header inclusions.
If you don’t do that, then configure the project so that any warning about skipping an include, yields a hard compilation error.
Instead of
iStream.setstate(std::ios::goodbit);
… do
istream.clear();
Instead of the non-portable Microsoft monstrosity
int _tmain(int argc, _TCHAR* argv[])
just use standard
int main()
or in C++11 trailing return type syntax,
auto main() -> int
Instead of
system("pause");
simply run your program via Ctrl+F5 in Visual Studio. Or, place a breakpoint on the last right brace of main and run in the debugger. Or, run the program from the command line.
The exercise formulation
” should read the stream until it hits end-of-file
is ambiguous, but anyway reading words, as you’re doing, does not faithfully reproduce whitespace in the stream. For a more accurate reproduction of the stream contents you can either read character by character, or (via getline) line by line. Or, you can use a special mechanism for this task, namely outputting the read buffer, which does everything in one little statement.
Finally, you don’t need all those headers. You only need <iostream>, and if you choose to read lines, also <string>. Also, you don’t need the return 0; at the end of main, because that’s the default.