CODEWITHSUNDEEP
python
Hamza Qaffaf
Hamza Qaffaf

Reputation: 1

Why does this code not output anything after getting user input?

num_1 = int(input("Enter the first number >>>>"))
num_2 = int(input("Enter the second number >>>>"))

if num_1 > num_2:
    for i in range(num_1,num_2+1):
        print(i)
else:
    for i in range(num_1,num_2,-1):
        print(i)

What is the issue with this code? Once the user inputs the two numbers the program stops and nothing gets printed.

Upvotes: 0

Views: 377

Answers (5)

sahasrara62
sahasrara62

Reputation: 11228

you are facing the error because you are using range function in wrong manner.

range(start, stop[, step]) -> range object

Here if step and start value is not provide then start value is consider as 0 by defualt and less than end value. also start is inclusive value and end is exclusive.

so in short range(start, end, step) -> start, start+step, start+step+step, ...., end-1`

in your code,

if num_1 > num_2:
   for i in range(num_1,num_2+1):
     # so on

here you are checking, if num_1>num_2, do for operation on range(num_1. num_2), so since step is not defined by you, it is taken as 1 by default

now the range(num_1, num_2) become [] as num_1 > num_2 and you cant reach num_2 by adding 1 to num_1 continousily. ie so list(range(num_1, num_2)) is [].

since it is empty for loop wont work and it exit the program. same happen (in opposite manner) when num_1<num_2.

to solve this you need to provide the correct value in range or change the if conditions.

so solution be like this

if num_1 < num_2:
    for i in range(num_1,num_2+1):
        print(i)
else:
    for i in range(num_1,num_2,-1):
        print(i)

Upvotes: 0

Carcigenicate
Carcigenicate

Reputation: 45736

To count from high to low, you need to do more than reverse the step. If you have, for example:

range(1, 10, -1)

This starts at 1, and attempts to count backwards. There are no numbers between 1 and 9 counting backwards from 1 though, so you get an empty collection:

>>> list(range(1, 10, -1))
[]

You need to reverse the arguments as well:

>>> list(range(10, 1, -1))
[10, 9, 8, 7, 6, 5, 4, 3, 2]

Upvotes: 0

Akshay Sehgal
Akshay Sehgal

Reputation: 19322

The issue is your first and second numbers are being used incorrectly in range.

The range takes smaller number first and larger number second. You are providing if num1 > num2 then get range(num1, num2) which is not iterating because no elements span from num1 to num2

num_1 = int(input("Enter the first number >>>>"))
num_2 = int(input("Enter the second number >>>>"))

if num_1 < num_2:
    for i in range(num_1,num_2+1):
        print(i)
else:
    for i in range(num_1,num_2,-1):
        print(i)

Enter the first number >>>>5
Enter the second number >>>>3
5
4

Upvotes: 0

Jean Camargo
Jean Camargo

Reputation: 400

num_1 = int(input("Enter the first number >>>>"))
num_2 = int(input("Enter the second number >>>>"))

if num_1 < num_2: # in here hace a less then sign and not > 
    for i in range(num_1,num_2+1):
        print(i)
else:
    for i in range(num_1,num_2-1): # In here you had a typo, it had a comma and as a result it was passing in 3 parameters
        print(i)

Upvotes: 0

Toffee
Toffee

Reputation: 75

You've got the logic the wrong way around. You need to check is num_1 is less than num_2 when counting up.

num_1 = int(input("Enter the first number >>>>"))
num_2 = int(input("Enter the second number >>>>"))

if num_1 < num_2:
    for i in range(num_1,num_2,+1):
        print(i)
else:
    for i in range(num_1,num_2,-1):
        print(i)

Upvotes: 1

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