Problem calculating area of a rectangle using decimal values in python3

Question

This program is written to find area of a rectangle.

l = float(input("Lenght of rectangle:"))
b = float(input("Breadht of rectangle:"))
area = l*b
print ("Area of square = l*b")
print ("               =",l,"*",b)
print ("               =",area)

The input length is 12.4 and the input breadth is 13 So the answer must be 161.2 however the answer coming is 161.20000000000002 What's going wrong?

Does this answer your question? [Is floating point math broken?](https://stackoverflow.com/questions/588004/is-floating-point-math-broken) — Ian Cook, Jan 31 '21 at 14:30

score 0 · Answer 1 · answered Jan 31 '21 at 14:18

0

Check out https://medium.com/code-85/how-to-stop-floating-point-arithmetic-errors-in-python-a98d3a63ccc8.

"This happens because decimal values are actually stored as a formula and do not have an exact representation."

answered Jan 31 '21 at 14:18

formicaman

1,317
3
16
32

Thank you but I couldn't understand it. Please tell if you have any other link. – Koustubh Sinha Jan 31 '21 at 15:54
Is there any way that we can only obtain two spaces after decimal. for example, instead of getting 1.345267, we only get 1.34. in other word we get only specific number of digit after decimal. – Koustubh Sinha Jan 31 '21 at 16:00
You can do something like `round(area, 2))` – formicaman Jan 31 '21 at 21:57

score 0 · Answer 2 · answered Jan 31 '21 at 16:10

Use the following program instead of the above one

l = float(input("Lenght of rectangle:"))
b = float(input("Breadht of rectangle:"))
area = (l*b)
a_float = "{:.2f}".format(area)
print ("Area of square = l*b")
print ("               =",l,"*",b)
print ("               =",area)

Here, we have format the program so that we only get two digits after the decimal. in this way the outcome will be similar to what we exactly wanted.

For more information, visit https://www.kite.com/python/answers/how-to-print-a-float-with-two-decimal-places-in-python#:~:text=Use%20str.,number%20with%20two%20decimal%20places.

reference:- www.kite.com

Problem calculating area of a rectangle using decimal values in python3

2 Answers2