CODEWITHSUNDEEP
pythonpython-3.x
StockAZ89
StockAZ89

Reputation: 51

Compare 3 numbers and return the largest

def max_num(num1, num2, num3):
  if num1 > num2 and num3:
    return num1
  elif num2 > num1 and num3:
    return num2
  elif num3 > num1 and num2:
    return num3

print(max_num(-10, 0, 10)) # first check, returns 0 (wrong)
print(max_num(-10, 5, -30)) # second check, returns 5 (right)
print(max_num(-5, -10, -10)) # third check, returns -5 (right)

I'm only something like 3 days into learning my first programming language (Python), and I was given a task to compare 3 numbers and return the largest. The 2nd and 3rd print checks are correct, as 5 and -5 are the largest out of their 3 numbers. However, the first check returns 0, which is obviously not the largest number, 10 is.

Upvotes: 0

Views: 3976

Answers (6)

Amir hesam Taheri far
Amir hesam Taheri far

Reputation: 1

a = int(input('Enter First Number:'))
b = int(input('Enter Second Number:'))
c = int(input('Enter Third Number:'))
max = 0
if a > max:
   max = a
if b > max:
   max = b
if c > max:
   max = c
print (max)

Upvotes: -2

Meduxa
Meduxa

Reputation: 1

I am new to coding and This is how i did it

       number_1= int(input("Enter first number"))
       number_2= int(input("Enter second number"))
       number_3= int(input("Enter third number"))
       if number_1 > number_2 and number_1 > number_3:
         print("the largest number", number_1)
       elif number_2 > number_1 and number_2 > number_3:
         print("The largest number is", number_1)
       elif number_3 > number_1 and number_3 > number_2:
         print("The largest number is",number_1)


       Enter first number 70
       Enter second number60
       Enter third number50

       the largest number 70

Upvotes: 0

Roei Duvdevani
Roei Duvdevani

Reputation: 76

Using the reserved word "and" in python in a condition, returns True only if both sides of it are True. An Integer is considered True if it's not zero. for Example:

num1 = 5
num2 = 1
num3 = 0
return num1 > num2 and num2 > num3 # returns True because all the conditions are true
return num1 > num2 and num1: # returns True because num1>num2 and num1 is not 0
return num1 > num2 and num3: # returns False because one of the conditions is False becuase num3 is 0

If so, the conditions you've sent are considered like:

if num1 > num2 and num3: # if num1 > num2 and num3 is not 0 

elif num2 > num1 and num3: # if num2 > num1 and num3 is not 0

elif num3 > num1 and num2: # if num3 > num1 and num2 is not 0

Therefore, the first one returns 0 because in the last condition you're checking if num2 is not 0 but it is.

A simple way to solve it:

def max_num(num1, num2, num3):
  if num1 > num2 and num1 > num3:
    return num1
  elif num2 > num1 and num2 > num3:
    return num2
  return num3

print(max_num(-10, 0, 10)) # returns 10
print(max_num(-10, 5, -30)) # returns 5
print(max_num(-5, -10, -10)) # returns -5

Upvotes: 1

Prudhvi
Prudhvi

Reputation: 1115

Your logical statement is not executing in the way you are thinking. In num1 > num2 and num3 it will check whether num1 is greater than num2 and num is 0 or not. you can change your conditons to num1 > num2 and num1 > num3. Try the following:

def max_num(num1, num2, num3):
  if num1 > num2 and num1 > num3:
    return num1
  elif num2 > num1 and num2 > num3:
    return num2
  elif num3 > num1 and num3 > num2:
    return num3

print(max_num(-10, 0, 10)) # returns 10
print(max_num(-10, 5, -30)) # returns 5
print(max_num(-5, -10, -10)) # returns -5

or like this:

def max_num(num1, num2, num3):
    if num1 > num2:
        if num1 > num3:
            return num1
        else:
            return num3
    else:
        if num2 > num3:
            return num2
        else:
            return num3

print(max_num(-10, 0, 10)) # returns 10
print(max_num(-10, 5, -30)) # returns 5
print(max_num(-5, -10, -10)) # returns -5

Upvotes: 1

Tristan Nemoz
Tristan Nemoz

Reputation: 2048

It is due to the fact that you can't factorize like this your condition. The condition:

if num1 > num2 and num3:
    ...

really means "If num1 is greater than num2 and num3 is different from 0". Indeed, Python tries to convert num3 into a boolean. If num3 is an empty list, an empty string, 0 or False, then it is evaluated to False. Otherwise, it is evaluated to True. What you really wanted to write is, for instance:

if num1 > num2 and num1 > num3:
    ...

Upvotes: 2

James Powis
James Powis

Reputation: 659

While this does answer your question, it does not fulfill the intent of your class.

max([1, 3, 2]) # 3

when using the and operator you should think of it as this.

if (condition) and (condition):

so use if num1 > num2 and num1 > num3:

Upvotes: 4

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