in C++

Frequency of occurrence of each letter

Write a program to calculate the frequency of occurrence of each letter in a given text file. Your program should distinguish between lower case and upper case letters. The text may contain characters other than alphabets. You can ignore the non-alphabetic characters but keep a count of it. You should also keep a count and display the number of non-alphabets, number of alphabets, number of upper-case and lower-case alphabets, numbers of charactersTas you read from the file.