需要把雙引號去掉。

<?php?

echo $m1 = memory_get_usage();?

echo "<br />";

$var_string = 123;

echo $m2 = memory_get_usage()-$m1;?

echo "<br />";

$n = 123;?

echo $m3 = memory_get_usage()-$m1-$m2;?

echo "<br />";

$f = 123.00;?

echo $m4 = memory_get_usage()-$m1-$m2-$m3;?

echo "<br />";

$var_array = array("123");

echo $m5 = memory_get_usage()-$m1-$m2-$m3-$m4;?

?>