$c0 = 1;
$c1 = 1;
$c2 = 0;
$c3 = 0;
$c4 = 1;
$c5 = 1;
for ($i = 0; $i < 6; $i++) {
echo ${'c' . $i};
}
But it would be better to declare a $c array, and so use from $c[0] to $c[5]
$c[] = 1;
$c[] = 1;
$c[] = 0;
$c[] = 0;
$c[] = 1;
$c[] = 1;
$num = count($c);
for {$i = 0; $i < $num; $i++) {
echo $c[$i];
}
or
$c[] = 1;
$c[] = 1
$c[] = 0;
$c[] = 0;
$c[] = 1;
$c[] = 1;
foreach ($c as $value) {
echo $value;
}