# [Tutor] Problem with "input" in Python 3

Peter Anderson peterjohnanderson at gmail.com
Tue Feb 16 00:18:38 CET 2010

```I seem to be having a formatting problem between Thunderbird on my PC
and the mailing list; I am loosing all indentation. The Gmail account
settings on Thunderbird are for plain text and I set the e-mail
content to fixed width text so I'm not sure what's going wrong. I am
trying one last time sending from Gmail (as fixed text).

#   A program that computes the real roots of a quadratic equation.
#   Bad version using a simple if to avoid program crash
#   This version uses the EasyGUI graphics library
#   See http://easygui.sourceforge.net/ for EasyGUI details

import math
from easygui import *

def main():

msg = "This program finds the real solutions to a quadratic" + "\n" + \
"Please enter the three coefficients below."
fieldNames = ["First coefficient","Second coefficient","Third coefficient"]
fieldValues = multenterbox(msg,title, fieldNames)

# make sure that none of the fields was left blank
while 1:
if fieldValues == None: break
errmsg = ""
for i in range(len(fieldNames)):
if fieldValues[i].strip() == "":
errmsg = errmsg + ('"%s" is a required field.' % fieldNames[i])
if errmsg == "": break # no problems found
fieldValues = multenterbox(errmsg, title, fieldNames, fieldValues)

a = int(fieldValues[0])
b = int(fieldValues[1])
c = int(fieldValues[2])

discrim = a * a - 4 * b * c
if discrim >= 0:
discRoot = math.sqrt(discrim)
root1 = (-a + discRoot) / (2 * b)
root2 = (-a - discRoot) / (2 * b)
message  = "The real solutions to the quadratic equation are "
+ str(root1) + " and " + str(root2)
ok_button="OK", image=None)

main()

--
There is nothing more difficult to take in hand, more perilous to
conduct, or more uncertain in its success, than to take the lead in
the introduction of a new order of things -- Niccolo Machiavelli, The
Prince, ch. 6
```