How Factorial Works In Code & Real Life Example

Factorial are the product of an integer and all the integers below it
eg: 2! = 2 * 1 = 2

Simple isnt it!

Now lets see how it work in our Javascript
Take a look at code below

//we created a function
function factorial(num) { 

  // initializing  
  var factorial = 1;

//using for loop we multiplied until num 
  for (var i = 1; i <= num; i++) {  
    // multiply each number between 1 and num  
    // factorial = 1 * 1 = 1
    // factorial = 1 * 2 = 2
    // factorial = 2 * 3 = 6
    // factorial = 6 * 4 = 24
    // ...
    factorial = factorial * i;
  }

 console.log(factorial);

}

// keep this function call here 
factorial(4);

output:

4*3*2*1 = 24

24

Got it! Right
BUT you might wonder what is practical use of it ..like in real life ..mmmmm good question

In real life we use it to find the no of outcomes ..like probability

Lets take an example:
do you love ice cream? i love a lot so we will use ice cream example..

Suppose you want 3 flavor scoop of ice cream on your cone
you choosed:

1. Chocolate
2. Strawberry
3. Vanilla

sounds sweets

Now which topping to put first or second or last on cone.....?

how many combination it will give so we use factorial

3 flavor so 3! > 3*2*1 = 6 combination
ie:

1. Chocolate-Strawberry-Vanilla
2. Chocolate-Vanilla-Strawberry
3. Strawberry-Vanilla-Chocolate
4. Strawberry-Chocolate-Vanilla
5. Vanilla-Strawberry-Chocolate
6. Vanilla-Chocolate-Strawberry

ahhh what a taste... now i am enjoying my ice cream
hope you have found this taste too :)