CODEWITHSUNDEEP
pythonpython-3.xwhile-loop
Tom Sparks
Tom Sparks

Reputation: 1

While loop problem.The result isn't what I expected

I am new to Python and Stackoverflow in general, so sorry if my formatting sucks and I'm not good at English. But I have a problem with this code.

n = int(input("Fibonacci sequence (2-10): "))
a = 0
b = 1
sum = 0
count = 1
f = True
print("Fibonacci sequence up to {}: ".format(n), end = " ") 
while(count <= n):
      print(sum, end = " ")
      count += 1
      a = b
      b = sum
      sum = a + b

This is the result of the code

Fibonacci sequence (2-10): 2
Fibonacci sequence up to 2: 0 1

And this is the result that I expect.

Fibonacci sequence (2-10): 1
Invalid Number!
Fibonacci sequence (2-10): 15
Invalid Number!
Fibonacci sequence (2-10): 10
Fibonacci sequence up to 10: 0 1 1 2 3 5 8 13 21 34

Upvotes: 0

Views: 51

Answers (1)

Prateek Dewan
Prateek Dewan

Reputation: 1631

Looks like you just need to add an additional validation step to make sure that the input is in the desired range. This should do it.

while True:
    n = int(input("Fibonacci sequence (2-10): "))
    if n<2 or n>10:
        print("Invalid Number!")
    else:
        a = 0
        b = 1
        sum = 0
        count = 1
        f = True
        print("Fibonacci sequence up to {}: ".format(n), end = " ") 
        while(count <= n):
              print(sum, end = " ")
              count += 1
              a = b
              b = sum
              sum = a + b
        break

Edit: To @Barmar's point, a loop on the outside would help avoid rerunning the code in case the input isn't within the desired range.

Upvotes: 2

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