Write a C program that implements rot13. Rot13 is a simple encoding technique (called substitution cipher) that takes an input string and replaces every letter with the letter 13 letters after it considering the alphabet to wrap back to itself. For ex. A <-> N, B <-> O, etc. Your code should handle both uppercase and lowercase letters but leave all other characters unmodified. Prompt the user for a string and print the rot13 value on the screen.