On 10/26/2013 1:36 PM, HC wrote:
I'm doing my first year in university and I need help with this basic
assignment.
Assignment: Write Python script that prints sum of cubes of numbers between
0-200 that are multiples of 3. 3^3+6^3+9^3+12^3....+198^3=?
My script:
count = 0
answer = 0
while count<200:
if count%3==0:
answer = answer + count**3
count = count + 1
print ("Result is: " +str(answer))
Is it all okay?
Generalize the problem, put the code in a reusable testable function,
and start with test cases.
--
def sum33(n):
"Return sum of cubes of multiples of 3 <= n."
for n, sm in ( (0,0), (2,0), (3,27), (4,27), (6,243), ):
assert sum33(n) == sm
print(sum33(200))
--
This will fail because None != 0. Now add 'return 0' and the first two
cases pass and then it fails with None != 27. Now change 'return 0' to
answer = 0
for i in range(3, n+1, 3):
answer += i*i*i
return answer
and it will print 131990067, which I presume is correct. Putting your
code in the body instead, indented, with '200' replaced with 'n+1', and
with 'return answer' added, gives the same result after passing the same
tests.
--
Terry Jan Reedy
--
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