## Q. Python Program to Find Factorial of a Given Number.

Here you will find an algorithm and program in Python programming language to find factorial of a number. First let us understand what factorial means.

Explanation : The factorial of a number is the product of all the integers from 1 to that number.

For Example : Factorial of 5 is 120 i.e. 5*4*3*2*1

## Algorithm to find factorial of a given number

```START
step 1 : Read the number n
step 2 : [Initialize]
i=1, fact=1
step 3 : Repeat step 4 through 6 until i=n
step 4 : fact=fact*i
step 5 : i=i+1
step 6 : Print fact
STOP

```

# Python Program to Find Factorial of a Number

```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("Error, 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("Factorial of",num,"=",factorial)
```

#### Output

```Factorial of 7 = 5040
```