#this program demonstrates how to use lists and 
#functions

#function get_values - will accept one parameter - size
#of the list and return randomly generated list of 
#integers

#function avesum will accept one parameter - list of 
#numbers and return sum and average of its elements

#function sumBook - gets one parameter - list of numbers
#returns sum of the elements using in LIST function
#example from the book 8.10 p.320

import random 

def sumBook(list_numbers):
	sum=0
	for num in list_numbers:
		sum=sum+num

	return sum

def avesum(list_numbers):
	
	size=len(list_numbers)
	sum=0
	
	for i in range(size):
		sum = sum + list_numbers[i]
	
	ave=float(sum)/size

	return sum, ave	



def get_values(size):
	
	numbers=[0]*size
	for i in range(size):
		numbers[i]=random.randint(1,100)
	
	return numbers
		
def main():
	size=random.randint(5,10)
	print("size of the list is ", size)
	
	list_numbers=get_values(size)
	print("the list is ")
	print(list_numbers)

	print("sum and average calculations")
	sumRes, aveRes = avesum(list_numbers)
	print("sum is ", sumRes)
	print("average is ", aveRes)
	print("sum calculation using function sumBook")
	sumRes=sumBook(list_numbers)
	print("sum is ", sumRes)

main()