Green eggs and ham

In a text that the user defines, VI created in this homework should count the number of different words and how many occurences of each of the words there are. As a textual template a programmer can use the lyrics of the well known song Green eggs and ham.

VI should ignore the character case and the use of punctuations marks and all the other special characters. Results should be stored in a cluster array where each cluster contains two elements: word and number of occurences of that word. VI should also in the end display the percentage of every word compared to the set of all words.