help please with this form broblem

[Syrman]

help please with this form broblem

---

Hello all

I have the following form

<FORM METHOD="POST" ACTION="">
<input name="checkbox" type="checkbox" value="checkbox" checked>
test1
<input name="checkbox2" type="checkbox" value="checkbox" checked>
test2
<INPUT NAME="name" TYPE=text id="name">
<INPUT NAME="email" TYPE=text id="email">
<INPUT NAME="city" TYPE=text id="city">
<INPUT name="submit" TYPE=submit id="Submt" VALUE="submit;">

which contains two checkboxes and other information, the problem I want to store the values entered by the user in three different text file.

1- If the user chose the first checkbox and enter his/her information the code will store the values to text a.

2- If the user chose the second checkbox and enter his/her information the code will store the values to text b.

3- If the user chose the two checkboxes (test1 and test2) and enter his/her information the code will store the values to text c.

I am new in PHP, could please helping me to solve this problem, which I have spent three days to solve it without any result.

Thank you in advance

[Kudose]

<?php
function write_file($file, $string){
	$handle = fopen($file, "a");
	$write = fwrite($handle, $string);
	if(!$write){
		echo "Error writing to file!";
		exit;
	} else {
	$msg = "Completed!";
	}
return $msg;
}
?>

<FORM METHOD="POST" ACTION="<?php $_SERVER['PHP_SELF']; ?>">
<input name="checkbox" type="checkbox" value="checkbox" checked>
test1
<input name="checkbox2" type="checkbox" value="checkbox2" checked>
test2
<INPUT NAME="name" TYPE=text id="name">
<INPUT NAME="email" TYPE=text id="email">
<INPUT NAME="city" TYPE=text id="city">
<INPUT name="submit" TYPE="submit" VALUE="submit">
</form>

<?php
if($_POST['submit']){
	$c1 = $_POST['checkbox'];
	$c2 = $_POST['checkbox2'];
	$name = $_POST['name'];
	$email = $_POST['email'];
	$city = $_POST['city'];

//format the string however you want, I am just
//formatting it this way to make it easy to turn
//it into an array later on down the road...
$string = $name.":".$email.":".$city."\n";

if((empty($c2)) && (!empty($c1))){
	$file = "/full/path/to/file.txt";
	write_file($file, $string);		
} elseif ((empty($c1)) && (!empty($c2))){
	$file = "/full/path/to/file.txt";
	write_file($file, $string);
} elseif ((!empty($c1)) && (!empty($c2))){
	$file = "/full/path/to/file.txt";
	write_file($file, $string);
} else {
	echo "There was an error detecting which file to write to.";
	exit;
}
}
?>

[Syrman]

Thank you very much Kudose.

Greetings