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finds the least common multiple and the greatest common factor of three numbers. i wrote it a while ago for school.

Python, 56 lines
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################################################################
# program name: least common multiple and gratest common facter
# author: max baseman
# email: dos.fool@gmail.com
# date: 01/16/07
# description: a program to find the LCM
#   and gcf of three given numbers
#
# 
################################################################
print
print
print"enter three numbers to get the LCM and gcf of"
num1=input("number 1 >")
num2=input("number 2 >")
num3=input("number 3 >")
#find the lowest number
if num1 < num2 and num1 < num3:
    low = num1
elif num2 < num1 and num2< num3:
    low = num2
elif num3 < num1 and num3 < num2:
    low = num3
# find the highest number
if num1 > num2 and num1 > num3:
    high=num1
elif num2 > num1 and num2 > num3:
    high=num2
elif num3 > num1 and num3 > num2:
    high=num3
# start at the largest number because the LCM cant be smaller then the highist number
number=high
#loop till finds the lowest number
while 1:
    numtest=number+.0
    if numtest/num1 == number/num1:
        if numtest/num2 == number/num2:
            if numtest/num3 == number/num3:
                break
    number=number+1
LCM=number
#apply number to LCM so that i can keep useing number for GCF
number=2
while number <=  low:
    numtest=number+.0
    if num1/numtest == num1/number:
        if num2/numtest == num2/number:
            if num3/numtest == num3/number:
                break
    number=number+1
else:
    number=1
GCF=number
print
print
print"the LCM was",LCM,"and the GCF was",GCF

this is a simple program that can be used for school purposes or just to shortin the time it takes to calculate by hand.

2 comments

Steven Bethard 14 years, 8 months ago  # | flag

min(), max() or sorted(). This is ugly:

if num1 &gt; num2 and num1 &gt; num3:
    low = num1
elif num2 &gt; num1 and num2 &gt; num3:
    low = num2
elif num3 &gt; num1 and num3 &gt; num2:
    low = num3
# find the highest number
if num1 &lt; num2 and num1 &lt; num3:
    high=num1
elif num2 &lt; num1 and num2 &lt; num3:
    high=num2
elif num3 &lt; num1 and num3 &lt; num2:
    high=num3

Ouch! Try using min() and max():

low = min(num1, num2, num3)
high = max(num1, num2, num3)

Or maybe sorted():

low, mid, high = sorted([num1, num2, num3])
greg p 14 years, 4 months ago  # | flag

Web Based Implementation. I made a web based GUI for a function like this calculating greatest common factor and least common multiple:

http://www.utilitymill.com/utility/GCF_and_LCM_Calculator

The code for it is listed here if you're curious: http://www.utilitymill.com/edit/GCF_and_LCM_Calculator

Created by max baseman on Sat, 24 Mar 2007 (PSF)
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