Factorial
Factorial is a mathematical operation denoted by the exclamation mark (!) symbol. It is used to calculate the product of all positive integers less than or equal to a given positive integer.
For example, the factorial of 5 is calculated as:
5! = 5 x 4 x 3 x 2 x 1 = 120
To compute the factorial of a non-negative integer n, denoted as n!, you need to multiply all the positive integers from 1 to n together.
Here's a step-by-step guide on how to calculate the factorial:
1. Start with the given non-negative integer, n.
2. Check if n is equal to 0 or 1. If so, the factorial is 1. Return the result.
3. If n is greater than 1, create a variable called "result" and set it equal to 1. This variable will store the factorial value.
4. Set up a loop that iterates from 2 to n. For each iteration, multiply the current value of "result" by the current number in the loop.
5. After the loop, the value of "result" will be the factorial of n.
6. Return the computed factorial value.
Here's a Python code snippet to calculate the factorial:
```python
def factorial(n):
if n == 0 or n == 1:
return 1
result = 1
for num in range(2, n + 1):
result *= num
return result
```
For example, if you want to find the factorial of 5, you would call the function like this:
```python
print(factorial(5)) # Output: 120
```
So, the factorial of 5 is 120.