Why is this not working when I input decimal numbers? It says incorrect despite both variables being equal

Asked Mar 12 '23 at 22:41

Active Mar 12 '23 at 22:43

Viewed 24 times

number1 = float(input("Enter the first number: "))
number2 = float(input("Enter the second number: "))

correct_answer = number1 * number2

answer = float(input(f"Enter {number1} * {number2} = "))

if  correct_answer == answer:
    print("Correct")
else:
    print("Incorrect")

print(f"It was {answer}")

I've been trying to get it to output "Correct" when I input 3 x 0.1 = 0.3, but it keeps outputting "Incorrect" even though answer == correct_answer.

edited Mar 12 '23 at 22:43

pr1nc3

8,108
3
23
36

asked Mar 12 '23 at 22:41

Ben

1

See: https://stackoverflow.com/questions/588004/is-floating-point-math-broken – slothrop Mar 12 '23 at 22:43
^ yup, and IIRC, 0.1 is one of those numbers that floating point arithmetic can't get 100% precise as there is no straightforward combination of powers of 2 that gives that. – DarkCygnus Mar 12 '23 at 22:45
1

see also https://stackoverflow.com/q/5595425/1358308 – Sam Mason Mar 12 '23 at 22:45
@Ben try printing the correct and the inputted answer, to see if they actually differ by a minuscule amount – DarkCygnus Mar 12 '23 at 22:46
1

or this recent blog post: https://jvns.ca/blog/2023/02/08/why-does-0-1-plus-0-2-equal-0-30000000000000004/ – Sam Mason Mar 12 '23 at 22:47

Why is this not working when I input decimal numbers? It says incorrect despite both variables being equal

0 Answers0