I had written a simple pascal triangle code in python but I am getting a error

def factorial(n):c=1re=1for c in range(n):re = re * c;return(re)print "Enter how many rows of pascal triangle u want to show \n"
n=input();
i=1
c=1
for i in range(n):for c in range(n-i-1):print ""for c in range(i):a = factorial(i);b = factorial(c);d = factorial(i-c);z = (a/(b*d));print "%d" % zprint "\n"

ERROR:

Traceback (most recent call last):File "/home/tanmaya/workspace/abc/a.py", line 19, in <module>z = (a/(b*d));
ZeroDivisionError: integer division or modulo by zero

Your factorial() function returns 0 for any input because of how you defined your range.

The range builtin starts at 0 unless otherwise defined so:

for c in range(n):re = re * c  # no semicolons in Python

is doing:

re = re * 0

on the first iteration so for all subsequent iterations:

re = 0 * c

will always be 0

Start your range at 1 like so

for c in range(1, n):re *= c  # The *= operator is short hand for a = a * b

you can see this more explicityly:

>>> print(list(range(5)))
[0, 1, 2, 3, 4]
>>> print(list(range(1,5)))
[1, 2, 3, 4]
>>> 

or instead of rolling your own function use the one that comes with Python:

>>> from math import factorial
>>> factorial(3)
6

Upon closer reading of your code it seems you tried to circumvent this by setting c = 1 outside your for loop. This is not going to work because the variables you declared outside the loop are being reassigned inside it.