in-and-out Needs an Existing File

Write a function bool openReadWrite(const string& filename) that opens filename with an fstream in ios::in | ios::out mode and returns whether the open succeeded (the result of is_open()). Do not write anything to the file, and print nothing to cout; the test prints the result itself.

The test prints opened when your function returns true and failed when it returns false. The first test creates data_a.txt before calling you, so it prints the output shown in Expected Output.

The second test passes the path missing_dir/data.txt, so it prints:
failed

Do NOT write a main function.