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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:

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

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <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>
</head>
<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:

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

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.


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Previous: Write a JavaScript program to check a number from three given numbers where two numbers are equal, find the third one.
Next: Write a JavaScript program to calculate the sum n + n/2 + n/4 + n/8 + .... where n is a positive integer and all divisions are integer.

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925