Someone

<?php

function a($start_index) {
for($i = $start_index; $i < 10; $i++) echo "\$i = $i\n";
}

a(false);

$i = null;

--$i;
var_dump($i); // NULL
$i--;
var_dump($i); // NULL

$i-=1;
var_dump($i); // int(-1)

 function change (&$var) {
   $var += 10;
 }

 $var = 1;
 ++$var;
 change($var);
 echo "var=$var";

 $var = 1;
 change(++$var);
 echo "var=$var";

$T = array();
$a = 0;
$b = 0;
$c = 0;

$T[$a] = ++$a; // [1]=1
$T[++$b] = ++$b; // [1]=2
$T[$c+=0] = ++$c; // [0]=1

var_dump($T);

$i = 'W';
for ($n=0; $n<6; $n++) {
    echo ++$i . "\n";
}

echo "<h3>Postincrement</h3>";
$a = 5;
echo "Should be 5: " . $a++ . "<br />\n";
echo "Should be 6: " . $a . "<br />\n";

echo "<h3>Preincrement</h3>";
$a = 5;
echo "Should be 6: " . ++$a . "<br />\n";
echo "Should be 6: " . $a . "<br />\n";

echo "<h3>Postdecrement</h3>";
$a = 5;
echo "Should be 5: " . $a-- . "<br />\n";
echo "Should be 4: " . $a . "<br />\n";

$a = 0;
$b = 1;
++$a.$b;



$a = 0;
$a++;
$a++;
$a++;
$a--;

++$a;
++$a;
++$a;
--$a;

echo $a;


class Tt {
var $counter;
}

$o = new Tt();
$o->counter++;
$o->counter++;
$o->counter++;
$o->counter--;

++$o->counter;
++$o->counter;
++$o->counter;
--$o->counter;

echo $o->counter;