PHP学习记录之函数二

<?php
 $price=50;
 $tax=0.5;
 function functionPrices(&$price,&$tax)
{
 $price=$price+$price*$tax;
 $tax=$tax*$tax;
}
functionPrices($price,$tax);
echo $price;
echo $tax;
?>

<?php
  $a=5;
  function f()
{
 global $a;
   $a=2;
}
//调用
f();
echo $a;//a=2;
?>

<?php
  $GLOBALS[‘a‘]=5;
 function f()
{
  $GLOBALS[‘a‘]=2;
}

//调用
f();
echo $GLOBALS[‘a‘];
?>