如何分配平均值并打印为 integer

Question

The instructions are to assign avg_owls with the average owls per zoo. Print avg_owls as an integer. However, the math keeps coming up wrong with the sample inputs. Even when I do the math by hand. The code is as follows.

Given sample inputs are 1 2 4

avg_owls = 0.0

num_owls_zooA = int(input())
num_owls_zooB = int(input())
num_owls_zooC = int(input())

avg_owls = int(num_owls_zooA + num_owls_zooB + num_owls_zooC / 3)

print('Average owls per zoo:', int(avg_owls))

Your output Average owls per zoo: 4 Expected output Average owls per zoo: 2

I have written and can only alter the code avg_owls = int(num_owls_zooA + num_owls_zooB + num_owls_zooC / 3)

I don't understand how it's coming up with 4 when the actual math comes out to 2.333

What am I doing wrong?

Answer 1

Operator precedence, and the rules of maths, say that

num_owls_zooA + num_owls_zooB + num_owls_zooC / 3

will be calculated as

num_owls_zooA + num_owls_zooB + (num_owls_zooC / 3)

You need some brackets to get the result you want:

(num_owls_zooA + num_owls_zooB + num_owls_zooC) / 3

As an extra note, applying int to the result feels potentially wrong. It will cause it to always round down. For an average you would usually want to either keep it as a floating point value or at least round to the nearest value rather than always down.

Answer 2

Two problems here. In pemdas or germdas, division comes before addition. SO you need parentheses around the addition. Also if you do int(4.3) you will get 4 . float will give you your desired output

avg_owls = 0.0

num_owls_zooA = float(input())
num_owls_zooB = float(input())
num_owls_zooC = float(input())

avg_owls = (num_owls_zooA + num_owls_zooB + num_owls_zooC) / 3

print(f'Average owls per zoo: {avg_owls} ')

also I suggest using f strings .

Answer 3

Change to:

avg_owls = int((num_owls_zooA + num_owls_zooB + num_owls_zooC) / 3)

This solution works as tested.