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JavaScript: Find the smallest prime number strictly greater than a given number

JavaScript Basic: Exercise-129 with Solution

Write a JavaScript program to find the smallest prime number strictly greater than a given number.

Pictorial Presentation:

JavaScript: Find the smallest prime number strictly greater than 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 smallest prime number strictly greater than a given number</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function next_Prime_num(num) {
    for (var i = num + 1;; i++) {
        var isPrime = true;
        for (var d = 2; d * d <= i; d++) {
            if (i % d === 0) {
                isPrime = false;
                break;
            }
        }
        if (isPrime) {
            return i;
        }
    }
}

console.log(next_Prime_num(3));
console.log(next_Prime_num(17));

Sample Output:

5
19

Flowchart:

Flowchart: JavaScript - Find the smallest prime number strictly greater than a given number

ES6 Version:

function next_Prime_num(num) {
    for (let i = num + 1;; i++) {
        let isPrime = true;
        for (let d = 2; d * d <= i; d++) {
            if (i % d === 0) {
                isPrime = false;
                break;
            }
        }
        if (isPrime) {
            return i;
        }
    }
}

console.log(next_Prime_num(3));
console.log(next_Prime_num(17));

Live Demo:

See the Pen javascript-basic-exercise-129 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to find the smallest round number that is not less than a given value.
Next: Write a JavaScript program to find the number of even digits in a given integer.

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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