如何在一个简单的数组中迭代所有可能的组合[关闭]

Kindly help me with my code:

$a[1]='cloropil';
$a[2]='rodopayta';
$r=2;
$c=1;
$f= while($c<=$r){ echo $a[$c];;
$e = $c++ };
while($c<=$r){
echo $f;
$r++;
}
while($c<=$r){
echo $e;
$r++;
}

I want its output to be like this:

$a[1]='cloropil';
$a[2]='rodopayta';
$r=2;
$c=1;
while($c<=$r){
 echo $a[$c];
   while($c<=$r){
    echo $a[$c];
    $c++;
   }
 $c++;
}

How ever the out put is blank. it should even display at least "cloropil". Is this even possible? I want to display something like this:

cloropilcloropil cloropilrodopyta rodopytacloropil rodopytarodopyta

thank you very much in advance.

I think this may be what you are looking for?:

<?php
$a[]='cloropil';
$a[]='rodopayta';

    // You first iterate over each
    for($i = 0; $i < count($a); $i++) 
        {
            // As you iterate through the first round, you iterate
            // again to match pairs but include the first iteration
            // value with this second 
            foreach($a as $val) 
                echo $a[$i].'=>'.$val.'<br />';
        }
?>

Gives you:

cloropil=>cloropil
cloropil=>rodopayta
rodopayta=>cloropil
rodopayta=>rodopayta