 # JavaScript: Find the number of trailing zeros in the decimal representation of the factorial of a given number

## JavaScript Basic: Exercise-112 with Solution

Write a JavaScript program to find the number of trailing zeros in the decimal representation of the factorial of a given number.

Pictorial Presentation: Sample Solution:

HTML Code:

``````<!DOCTYPE html>
<html>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title> Find the number of trailing zeros in the decimal representation of the factorial of a given number</title>
<body>

</body>
</html>
```
```

JavaScript Code:

``````function trailing_zeros_factorial(n) {
var result = 0;
for (var i = 5; i <= n; i += 5) {
var num = i;
while (num % 5 === 0) {
num /= 5;
result++;
}
}
return result;
}

console.log(trailing_zeros_factorial(8))
console.log(trailing_zeros_factorial(9))
console.log(trailing_zeros_factorial(10))
``````

Sample Output:

```1
1
2
```

Flowchart: ES6 Version:

``````function trailing_zeros_factorial(n) {
let result = 0;
for (let i = 5; i <= n; i += 5) {
let num = i;
while (num % 5 === 0) {
num /= 5;
result++;
}
}
return result;
}

console.log(trailing_zeros_factorial(8))
console.log(trailing_zeros_factorial(9))
console.log(trailing_zeros_factorial(10))
``````

Live Demo:

See the Pen javascript-basic-exercise-112 by w3resource (@w3resource) on CodePen.

What is the difficulty level of this exercise?

﻿

## JavaScript: Tips of the Day

Parameter's value

```function getItems(fruitList, ...args, favoriteFruit) {
return [...fruitList, ...args, favoriteFruit]
}

getItems(["banana", "apple"], "pear", "orange")
```

...args is a rest parameter. The rest parameter's value is an array containing all remaining arguments, and can only be the last parameter! In this example, the rest parameter was the second parameter. This is not possible, and will throw a syntax error.

```function getItems(fruitList, favoriteFruit, ...args) {
return [...fruitList, ...args, favoriteFruit];
}

getItems(['banana', 'apple'], 'pear', 'orange');```
The above example works. This returns the array [ 'banana', 'apple', 'orange', 'pear' ].

Ref: https://bit.ly/3jFRBje