CODEWITHSUNDEEP
pythonpython-3.xrecursionreturn-value
Rebecca Maria
Rebecca Maria

Reputation: 11

why my return function is not working python

initialValues = input('Please enter a space separated set of values for y, h and g(0): ')

values = []
values.append(initialValues)

theValues = []

for item in values:
    item = item.split(' ')
    for index in range(len(item)):
        item[index] = int(item[index])
    theValues.append(item)

y = theValues[0][0]
h = theValues[0][1]
g0 = theValues[0][2]

def Sumrecur(y,h,g0):
    if y == 0 :
        return g0
    else:
        sum = 0
        for k in range(1,y):
            sum = sum + Sumrecur(k,h,g0)*h
    return sum

Sumrecur(y,h,g0)

this is a function i'm currently working on. I'm confused as the return sum command doesn't work. Is there anything wrong with the code?? Sorry it might sound silly to some of you but I really don't know how to fix this. thanks before!

Upvotes: 0

Views: 311

Answers (2)

Abhimanyu singh
Abhimanyu singh

Reputation: 417

TL;DR : I would try using range(0,y) in your for loop.

BREAKDOWN: Your recursion depends on the value of y and only ends whenever y equals 0 .

Lets see how the recursions are called using an example

STEP 1 Sumrecur(3,1,1) will call Sumrecur(1,1,1) and Sumrecur(2,1,1)

STEP 2a : Sumrecur(1,1,1) calls nothing

STEP 2b : Sumrecur(2,1,1) calls Sumrecur(1,1,1)

STEP 3: Sumrecur(1,1,1) calls nothing

You see what the issue is ? The value of y never equals 0 , so it never enters the 

   if y == 0 :
      return g0

I would try using range(0,y) in your for loop.

Upvotes: 0

TLOwater
TLOwater

Reputation: 638

Once you've gone 1 recursion deep you need to return multiple times to actually return the value. Basically you've returned the value to the last recursion but this isn't the original one you called so there will be no output. Maybe write to a global variable or print the value instead.

Upvotes: 1

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