Write a C++ program that accepts a string of characters of unlimited length from user and produces the Huffman code for each character. Please explain how your program finds frequencies and say what lines of code accomplish this. Also explain how your program accomplishes sorting by frequency, building the tree and generating the codes (and what lines of code do each task). Please write the runtime function as a function of the number distinct characters in the input. Please also show a screen shot of output with a input that is at least 50 characters.