Computer >> Computer tutorials >  >> Programming >> Python

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

Python Program for factorial of a number

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

Python Program for factorial of a number

Conclusion

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