A factorial is positive integer n, and denoted by n!. Then the product of all positive integers less than or equal to n.
For example:
In this article, we are going to calculate the factorial of a number using recursion.
Examples:
Input: 5 Output: 120 Input: 6 Output: 720
Implementation:
If fact(5) is called, it will call fact(4), fact(3), fact(2) and fact(1). So it means keeps calling itself by reducing value by one till it reaches 1.
Python3
# Python 3 program to find # factorial of given numberdef factorial(n): # Checking the number # is 1 or 0 then # return 1 # other wise return # factorial if (n==1 or n==0): return 1 else: return (n * factorial(n - 1))# Driver Codenum = 5;print("number : ",num)print("Factorial : ",factorial(num)) |
Output
number : 5 Factorial : 120
Time complexity: O(n)
Space complexity: O(n)
