[Tutor] LCM

Alan Gauld alan.gauld at btinternet.com
Thu Oct 21 10:14:39 CEST 2010

"Jacob Bender" <benderjacob44 at gmail.com> wrote

> decided to make a program that deals with them. Here's the code:
> thing = raw_input("What is the first number?\n\n")
> thing2 = raw_input("What is the second number?\n\n")
> int(thing)
> int(thing2)

This does nothing useful. It converts the strings to numbers
which are immediately thrown away because they are not
assigned to anything.

> x = 1
> thing3 = x/thing
> thing4 = thing2/x

This will likely fail because things are still strings.
But even if they were numbers itwould be clearer
in this case to not use x, just put the 1 directly in
the calculation.

> def calc():
>     while True:
>         if isinstance(thing3, int) == True:
>             if isinstance(thing4, int)== True:
>                 print "The LCM is"
>                 print x

So any time thing3 and 4 are integers x will be 1

>                 raw_input()
>                 break

>             else:
>                 x + 1

Again this does nothing useful because it adds one to x
then throws away the value

>                 calc()

This will cause an infinite loop (until Python runs
out of recursion space). I'm not even sure what
you think this will achieve?

>         else:
>             x + 1
>             calc()

See above...

> The only problem is that when I tell it that thing3 = x/thing it 
> gives an error. Here it is:
> Traceback (most recent call last):
>   File "C:/Documents and Settings/Family/My Documents/LCM.py", line 
> 10, in <module>
>     thing3 = x/thing
> TypeError: unsupported operand type(s) for /: 'int' and 'str'

See above comments.

You need to retyhink your algorithm and pay attention to assigning
results to variables.

And once you have done that you may want to make x a parameter
of calc(), or at least declare it a global variable.

Alan Gauld
Author of the Learn to Program web site

More information about the Tutor mailing list