JavaScript: Sort an array of all prime numbers between 1 and a given integer

Last update on May 30 2022 10:07:40 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-109 with Solution

Write a JavaScript program to sort an array of all prime numbers between 1 and a given integer.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title> Sort an array of all prime numbers between 1 and a given integer</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function sort_prime(num) {

  var prime_num1 = [],
      prime_num2 = [];
  for (var i = 0; i <= num; i++) {
    prime_num2.push(true);
  }
  for (var i = 2; i <= num; i++) {
    if (prime_num2[i]) {
      prime_num1.push(i);
      for (var j = 1; i * j <= num; j++) {
        prime_num2[i * j] = false;
      }
    }
  }

  return prime_num1;
}

console.log(sort_prime(5))
console.log(sort_prime(11))
console.log(sort_prime(19))

Sample Output:

[2,3,5]
[2,3,5,7,11]
[2,3,5,7,11,13,17,19]

Flowchart:

ES6 Version:

function sort_prime(num) {
  const prime_num1 = [];
  const prime_num2 = [];
  for (var i = 0; i <= num; i++) {
    prime_num2.push(true);
  }
  for (var i = 2; i <= num; i++) {
    if (prime_num2[i]) {
      prime_num1.push(i);
      for (let j = 1; i * j <= num; j++) {
        prime_num2[i * j] = false;
      }
    }
  }

  return prime_num1;
}

console.log(sort_prime(5))
console.log(sort_prime(11))
console.log(sort_prime(19))

Live Demo:

See the Pen javascript-basic-exercise-109 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to find the number of even values in sequence before the first occurrence of a given number.

JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04