The factorial of a number is the product of all the integers from 1 to that number.
For example, the factorial of 6 is 1*2*3*4*5*6 = 720
. Factorial is not defined for negative numbers, and the factorial of zero is one, 0! = 1
.
Source Code
# Python program to find the factorial of a number provided by the user.
# change the value for a different result
num = 7
# To take input from the user
#num = int(input("Enter a number: "))
factorial = 1
# check if the number is negative, positive or zero
if num < 0:
print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("The factorial of",num,"is",factorial)
Output
The factorial of 7 is 5040
Note: To test the program for a different number, change the value of num
.
Here, the number whose factorial is to be found is stored in num
, and we check if the number is negative, zero or positive using if...elif...else
statement. If the number is positive, we use for
loop and range()
function to calculate the factorial.