a)
Write a program that will find the smallest, largest and average values in
a collection of N numbers. Get the value of N before scanning each value
in the collection of N numbers.

b) Modify your program to compute and display both the range of values
in the data collection and the standard deviation of the data collection. 
To compute the standard deviation, accumulate the sum of the squares of 
the data values (sum_squares) in the main loop. After loop exit, use
the formula 
		standard_deviation = sqrt( sum_squares/N - average*average)

Ref. Hanly, Ch. 5, P2, p.285