c program : You are now allowed to use the following in additional to the techniques of the previous chapters: pointers pointer operators pass by reference simulation const qualifiers sizeof operator function pointers

character handling library string handling library string conversion functions additional input/output functions from getchar() fgets() putchar() puts() sprintf() sscanf()

Q3: (Letter Frequency Analysis) (25 points) One important tool for deciphering encrypted text is to study the frequency of letters or groups of letters. Write a program that will allow the user to enter several sentences, and then produce a frequency analysis for each letter. The program should state which letter occurred the most often. Uppercase letters and lowercase letters should be treated the same. Ignore any punctuation symbols that were entered. Sample output:

Letter Frequency:

a-10

b-2

c-4

d-11

...

The letter 'e' was the most frequently used letter.