I need some help writing this code, and how do you compare things in a file that are not in an array?

Name this program count.c The program takes a single command line argument, the name of an input file.

Your program should confirm the input file exists (exit with an appropriate error message if it does not).

If the file exists, then count the number of upper-case and lower-case letters in the file.

Print your counts to standard output.