Write a program that will compute the average word length (average

number of characters per word) for a file that contains some text. A

word is defined to be any string of symbols that is preceded and followed

by one of the following at each end: a blank, a comma, a period,

the beginning of a line, or the end of a line. Your program should define

a function that is called with the input-file stream as an argument. This

function should also work with the stream cin as the input stream,

although the function will not be called with cin as an argument in this

program. If this is being done as a class assignment, obtain the file

names from your instructor.