Fix inconsistent indentation
Make ifstream usage more idiomatic.

Testing the stream state explicitly is an anti-pattern, it is better to
check the result of the read operation directly.

Closing the ifstream happens automatically at scope exit anyway.

The string variable doesn't need to be declared until point of use.

Fix spelling of "successful".
Use boolean to indicate success or failure.

Idiomatic C++ uses bool return values not 0 or 1.

Fix the error message printed.
Write errors to std::cerr not std::cout.
Fix poor C++ style.

Header files should have include guard macros.
Header files should never pollute the global namespace with 'using'.
Only include <iostream> when actually needed.
Members should be initialized in the ctor-initializer-list.
Merge pull request #19 from jwakely/fix-cxx-files

Improve example C++ files