Write a program that will read an unspecified number of positive numbers from the keyboard and determine the sum and the average of these numbers. A negative number should be used to terminate the input, i.e. when the program encounters a negative number, it should stop prompting and reading data and at that point should output the results. Note that the negative number that terminates the looping should not be added to the sum and certainly should not be counted as one of the valid numbers.