This is a basic Python program which helps school and college students to improve their knowledge in Python.

If you don’t know what is factorial, here is a small explanation,

Multiplying given integer with the sequence of descending positive integers is called factorial. For example,

**5!** is 5 x 4 x 3 x 2 x 1 = **120
**So the value of

**5!**is

**120**

We can also find the values in the reverse way ie.,

**5!** is 1 x 2 x 3 x 4 x 5 = **120**

In this program we are going to follow the above second method to find the value of the **n!** (n factorial)

Now, lets see the Python Factorial Program here:

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print ("Enter Number to calculate Factorial: ") #get the input n = int(input()) fact = 1 print ("Factorial of", n, "is:") #loop range from 1 to n for i in range(1, n + 1): fact = fact * i print (fact) |

This code works in both the **Python 2** and** Python 3** versions.

Let’s see the CGI version aka Python web version of this program:

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#!/usr/bin/python print "Content-type: text/html\n\n"; # Import modules for CGI handling import cgi, cgitb print ''' <html> <head><title>Python CGI program to find n! (n factorial)</title></head> <body> <h3>Web Based Factorial Python script to find n! - <a href="http://www.tutorialsmade.com/">Tutorialsmade.com</a></h3> <form action="" method="post"> <label>Enter Number to calculate Factorial:<label> <input type="text" name="n" /> <input type="submit" value="Submit" /> </form><br /><br /> </body> </html> ''' # Create instance of FieldStorage form = cgi.FieldStorage() #get the input n = form.getvalue('n') if(n): #type case string to int n = int(n) fact = 1 print "Factorial of", n, "is:", "<br>" #loop range from 1 to n for i in range(1, n + 1): fact = fact * i print fact,"<br>" |

It’s same as the normal Python application program but the only difference is the extra Form added in this script.

Here is the demo of the above script: