Write a C++ program that is given a file name as a command line argument.

Open the file and read it. At the end of the file, print out:

LINES: lc WORDS: wc CHARS: cc DIGITS: dc

Where lc is the number of lines, wc is the number of words, cc is the number of characters, and dc is the number of digit characters, 0-9.

If no file name is provided, the program should use the standard input instead of a file.

If the file cannot be opened, print "CANNOT OPEN " followed by a space and the filename, and stop.

The program should ignore any extra command line arguments that are provided after the file name.

NOTE:

For reasons (that were stupid in retrospect), the name of the test cases isn't necessarily the name of the files.

The case named "cantopen" has the expected answer in files1.correct. The case named "empty" uses files1 and has the expected answer in files2.correct The case named "stdin" uses files2 and has the expected answer in files3.correct The case named "files" uses files3 and has the expected answer in files4.correct