Question

Exercise 2. Automate the boring stuff, page 77, Input Validation. Add try and except statements to the previous project to detect whether the user types in a noninteger string. Normally, the int() function will raise a ValueError error if it is passed a noninteger string, as in int('puppy'). In the except clause, print a message to the user saying they must enter an integer.

THis is the previous project

#function definition
def collatzSequence(number):
#
    if number % 2 == 0:
        print((number) // 2)
        return number // 2

    else:
        nextNumber = 3*(number)+1
        print(nextNumber)
        return nextNumber

n = input("Please input an integer: ")
while n != 1:
    n = collatzSequence(int(n))

Answer 1

SOURCE CODE:

*Please follow the comments to better understand the code.

**Please look at the Screenshot below and use this code to copy-paste.

***The code in the below screenshot is neatly indented for better understanding.

#function definition
def collatzSequence(number):
#
if number % 2 == 0:
print((number) // 2)
return number // 2

else:
nextNumber = 3*(number)+1
print(nextNumber)
return nextNumber

while True:
n = input("Please input an integer: ")
try:
n=int(n)
break
except:
print('INVALID.. Please Enter an Integer.')
  
while n != 1:
n = collatzSequence(int(n))

==========================

SCREENSHOT: