c++ program-count distinct characters

1. Accepts an input file name from the user
2. If the input file can not be opened, display an appropriate message and end the program.
3. For each distinct character in the file, display a count of the number of times that character appears in the file.

• Use an array to count the number of times each ASCII character appears in the file
• Use a while loop to read each character of the file
• After reading the file, use a for loop to display the non-zero contents of your array