Why aren't the contents of my text file printing in python?

Question

I am trying to open a file after I have changed the contents of it. After I changed the contents, the file will not open and will not produce an output.

first part of code

second part of code where issues are occuring

Answer 1

HINT (as this is clearly homework): instead of

   ...
   print(x)

how might you write to the file fnumbers ?

Answer 2

You forgot to use the write method in Question 4, hence that is why there is no data to be read in Question 5

fnumbers = open("cube_numbers.txt", "w")
for num in range(1,20):
    if num % 2 != 0:
        x = num ** 3
        fnumbers.write(str(x) + "\n" )
fnumbers.close()

To answer Question 5, first open the file with read method and simply use for loop

fnumbers = open("cube_numbers.txt", "r")
sum = 0;

for num in fnumbers:
    number = int(num)
    if(number % 3 == 0):
        print(number)
        sum = sum + number
print("sum = ", sum)
fnumbers.close()