Write a program, ww.c (pronounced “word word”), that reports duplicate adjacent words in text. A word is a string of alphabetic characters, delimited by non-alphabetic characters or file boundaries. As an argument ww takes the name of zero or more files. When duplicates are found, the program prints the filename, line of the first instance, and the lowercase word all separated by colons. The program should be insensitive to case. It leaves with nonzero exit status only when pairs are found.