#!/usr/bin/env python
# coding=utf-8
"""
try... except
"""
while 1:
print "this is a division program."
c = raw_input("input 'c' continue, otherwise logout:")
if c == 'c':
a = raw_input("first number:")
b = raw_input("second number:")
try:
print float(a)/float(b)
print "*************************"
#except ZeroDivisionError:
# print "The second number can't be zero!"
# print "*************************"
#except ValueError:
# print "please input number."
# print "************************"
except:
print "some wrong..."
print "********************"
else:
break