Exercise : Prime Factors XML (by Eli White)

Write a PHP web service factors-xml.php that computes and outputs prime factorization of integers as XML. (sample solution) (solution code) Provide the following behavior:

A GET request to factors.php with an n parameter outputs the prime factors of that integer. For example, the request factors.php?n=264 would output:
```
<integer value="264">
	<factor>2</factor>
	<factor>2</factor>
	<factor>2</factor>
	<factor>3</factor>
	<factor>11</factor>
</integer>
```
One algorithm for prime factorization of n is to loop through each integer i from 2-n, and for each time n is divisible by i, add i to your list of prime factors.
A GET request without a proper n parameter should return an HTTP error code 400 (Invalid Request) with an instructive error message.

Exercise : Prime Factors JSON (by Eli White)

Write a PHP web service factors-json.php that computes and outputs prime factorization of integers as JSON. (sample solution) (solution code) Provide the following behavior:

A GET request to factors.php with an n parameter outputs the prime factors of that integer. For example, the request factors.php?n=264 would output:
```
{"value": 264, "factors": [2, 2, 2, 3, 11]}
```
One algorithm for prime factorization of n is to loop through each integer i from 2-n, and for each time n is divisible by i, add i to your list of prime factors.
A GET request without a proper n parameter should return an HTTP error code 400 (Invalid Request) with an instructive error message.