#Read in the contents of the CSV file
fin = open('exam_grades_small.csv','r')
contents = fin.read()
fin.close()  #done with fin, so let's close it right away

#Let's create a stream to output our results to
fout=open('exam_grades_results.txt','w')

#Recall that 'contents' holds the entire CSV file as one long string
#Each grade is separated from the next by a comma
#We need to separate out these grades

numbers = contents.split(',')
#'numbers' is now a list of all the numbers in the file
#IMPORTANT: Those numbers are still strings though (Recall that we read in the file as a string)

#Let's calculate the average:
total = 0
for num in numbers:
    print()
    print(num,'\t',type(num))  #Note that it is a string
    
    print('Now let\'s cast to an integer:')
    num = int(num) #cast the string to an integer
    print(num,'\t',type(num)) #note that it is NOW an integer!
    
    total += num
    
    #Let's write the current status to the file:
    s = 'Current number:{0}\tCurrent sum:{1}'.format(num,str(total))
    fout.write(s+'\n')
    #fout.write('Current sum: '+str(total)+'\n')  #write can ONLY accept a STRING as its argument!

#Now that we have the sum of all the numbers, get the average
mean = total / len(numbers)
mean = round(mean,1)
print("Average: ", mean)

fout.write('The average of all the numbers is {}'.format(str(mean)))
fout.close()