register.php

<?php

$dataFile = 'ss.dat';			
$cleandate = $_POST['cleandate'];
$userhouse = $_POST['userhouse'];
$coinlaundry = $_POST['coinlaundry'];
$cost = $_POST['cost'];
echo $cleandate;
echo $userhouse;
echo $cost;
echo $coinlaundry;

if($_SERVER['REQUEST_METHOD']=='POST' &&
	isset($_POST['cleandate'])&&
	isset($_POST['userhouse'])&&
	isset($_POST['userid'])&&
	isset($_POST['coinlaundry']) && 
	isset($_POST['cost'])
	){

	$cleandate = $_POST['cleandate'];
$userhouse = $_POST['userhouse'];
$userid = $_POST['userid'];
$coinlaundry = $_POST['coinlaundry'];
$cost = $_POST['cost'];

$fp   = fopen($dataFile, "r");
while (($dataRow = fgetcsv($fp, 0, ",")) !== FALSE) {
	$dataArray[] = $dataRow;
}
fclose($fp);

foreach ($dataArray as $key => $eachData) {
	if($eachData[0]== $cleandate and
		$eachData[1]== $userhouse and
		$eachData[2]== $userid){
		// ３要素が同じ時、dataArrayを書き換える。elseの時はデータを
		// // 付け加える	
		$a = $key;
		// dataArray[$key][3]=$coinlaundry;
		// dataArray[$key][4]=$cost;
}
}

if($a != null){
	// 書き換える
	$dataArray[$a][3] = $coinlaundry;
	$dataArray[$a][4] = $cost;
	$fp=fopen($dataFile,'w');
	foreach ($dataArray as $eachData) {
		$reData .= $eachData[0] . "," . $eachData[1] . "," . $eachData[2] . "," . $eachData[3] . "," . $eachData[4] . "\n";
		# code...
	}
	fwrite($fp,$reData);
	fclose($fp);

}else{
	// 付け加える
	$newData=$cleandate . "," . $userhouse . "," . $userid . "," . $coinlaundry . "," . $cost . "\n";
	$fp=fopen($dataFile,'a');
	fwrite($fp,$newData);
	fclose($fp);
}
}
?>