Factorial of a number entered by User

Factorial :-

The factorial (represent with symbol: ! ) multiply all whole numbers from our chosen number down to 1.

The general formula of factorial can be written in fully expanded form as :-

n! = n x (n-1) x (n-2) x ...x 3 x 2 x 1.
or in partially expanded form as
n! = n  x (n-1)!.


Examples :-

1! = 1
3! = 3 x 2 x 1 = 6
4! = 4 × 3 × 2 × 1 = 24
7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040
0! = 1

n! = n x (n-1)!
1! = 1 x (1-1)!
1! = 1 x (0)!

0!=must be equal to 1 then only it give the result as 1.

1! = 1

Implimentatin of factorial program:-

n =int(input("Enter the number to find factorial: "))
fact=1
if(n<0):
    print("Factorial is not possible for negative number! ")
elif(n==0 or n==1):
    print("The factorial of ",n," is ",fact)
else:
    for i in range(1,n + 1):
        fact = fact*i
    print("The factorial of ",n," is ",fact)