Python Program for factorial of a number

In this article, we will learn about the solution and approach to solve the given problem statement.

Problem statement −Our task to compute the factorial of n.

Factorial of a non-negative number is given by −

n! = n*n-1*n-2*n-3*n-4*.................*3*2*1

We have two possible solutions to the problem

• Recursive approach
• Iterative approach

Approach 1 −Recursive Approach

Example

def factorial(n): # recursive solution
   if (n==1 or n==0):
      return 1
   else:
      return n * factorial(n - 1)
# main
num = 6
print("Factorial of",num,"is", factorial(num))

Output

('Factorial of', 6, 'is', 720)

All the variables are declared in global scope as shown in the image below

Approach 2 −Iterative Approach

Example

def factorial(n):# iterative solution
   fact=1
   for i in range(2,n+1):
      fact=fact*i
   return fact
# main
num = 6
print("Factorial of",num,"is", factorial(num))

Output

('Factorial of', 6, 'is', 720)

All the variables are declared in global scope as shown in the image below

Conclusion

In this article, we learned about the approach to compute the factorial of a number n.