Find factorial of a number using for loop , while loop and recursion in python :
What is factorial :
Factorial of a number is the multiplication of all the numbers from 1 to that number e.g. factorial of 3 is 1 * 2 * 3 i.e. 6 . To find factorial, we can either use loops or recursive approach. Following examples will explain you properly how to find factorial of a number in python :
Using for loop :
Using for loop we can iterate from 1 to that specific number we want to find out factorial . On each iteration , we will multiply the final result with current iteration count . final result will be 1 at first. So, after the loop will exit, we will get the factorial of that number .
def factorialUsingForLoop(n): fact = 1 for i in range(1,n+1): print (i) fact=fact*i print('Factorial of the number %d is %d'%(n,fact)) if __name__== "__main__": factorialUsingForLoop(4)
Find factorial using while loop :
We can similarly find out the factorial of a number using a while loop. On each time , we will decrease the value of the number by 1 and multiply it with the final result.
def factorialUsingWhileLoop(n): fact = 1 while(n>1): fact = fact*n n = n - 1 print('Factorial is %d'%(fact)) if __name__== "__main__": factorialUsingWhileLoop(4)
Factorial using Recursion :
Recursion means the same function will be called recursively. To find factorial of a number, we can also use recursive approach like below :
def factorialUsingRecursion(n): if (n == 1): return 1 else : return n* factorialUsingRecursion(n-1) if __name__== "__main__": print "factorial is ",factorialUsingRecursion(4)