Write a program that will read a line of text that ends with a period, which serves as a sentinel value. Display all the letters that occur in the text, one per line and in alphabetical order, along with the number of times each letter occus in teh text. Use an array of base type int of length 26, so that the element at index 0 forth. allow both uppercase and lowercase letters as input, but treat uppercase and lowercase verisons of the same letter as being equal.