# JavaScript: Check a given number is an ugly number or not

## JavaScript Math: Exercise-100 with Solution

Write a JavaScript program to check if a given number is ugly.

Ugly numbers are positive numbers whose only prime factors are 2, 3 or 5. The first 10 ugly numbers are:

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, ...

Note: 1 is typically treated as an ugly number.

**Visual Presentation:**

**Test Data:**

(12) -> true

(18) -> true

(19) -> false

**Sample Solution:**

**JavaScript Code:**

```
/**
* Function to check if a number is an ugly number.
* @param {number} n - The number to check.
* @returns {boolean} - Returns true if the number is an ugly number, otherwise false.
*/
function test(n) {
map = [5, 3, 2]; // Array of prime factors that define an ugly number
for (let i = 0; i < map.length && n > 1; i++) { // Iterate through the prime factors array
while (n % map[i] === 0) n /= map[i]; // Divide the number by the current prime factor if it's divisible by it
}
return n === 1; // If the number becomes 1 after dividing by all prime factors, it's an ugly number
};
// Test cases
n = 12;
console.log("n = " +n);
console.log("Check the said number is an ugly number? "+test(n));
n = 18;
console.log("Original text: " +n);
console.log("Check the said number is an ugly number? "+test(n));
n = 19;
console.log("Original text: " +n);
console.log("Check the said number is an ugly number? "+test(n));
```

Output:

n = 12 Check the said number is an ugly number? true Original text: 18 Check the said number is an ugly number? true Original text: 19 Check the said number is an ugly number? false

**Flowchart: **

**Live Demo: **

See the Pen javascript-math-exercise-100 by w3resource (@w3resource) on CodePen.

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