麻烦的索引PHP

for($c=1;$c<=$num;$c++)
{

$row=mysql_fetch_array(mysql_query("SELECT * FROM `$quiztitle` WHERE id=$c"));

        if($row['answer']==$_POST['answer'][$c]) // NOT WORKING
            {
                echo "correct";
                echo "<br>";
            }

        else
            {
                echo "incorrect";
                echo "<br>";
            }
    }

on the line where it says "NOT WORKING", the index [$c] does not get the value from the loop. but when i specify it and change it to $_POST['answer1'], it is working. what is the correct syntax for this?

Based on your note, it looks like you want:

$_POST["answer$c"]

Correct is:

if ($row['answer'] == $_POST['answer' . $c]) {
  ....
}

Try this.

for($c=1;$c<=$num;$c++) {

 $row=mysql_fetch_array(mysql_query("SELECT * FROM `$quiztitle` WHERE id=$c"));

    if($row['answer']==$_POST['answer'.$c]) // NOT WORKING
        {
            echo "correct";
            echo "<br>";
        }

    else
        {
            echo "incorrect";
            echo "<br>";
        }
}

You're treating 'answer' as an array here, looking for an index within.

You want to concatenate the value.

if($row['answer']==$_POST["answer{$c}'])