<?php
 
function isgreater($a, $b) {
   if($a > $b)
     return 1;
   else 
     return 0;
}
 
//function only can pass value or reference, eg: function xxx(2, isgreater)
//compare with c programming, php is no datatype define, so the function can pass to it //directly.
function compare($num1, $num2, &$func) {
 
//$funcpointer = & $func;
 
//return $funcpointer($num1, $num2);
 
return $func($num1, $num2);
 
}
 
$num1 = 100;
$num2 = 50;
 
 
if(compare($num1, $num2, isgreater)) 
printf("num1 is greater than num2");
 
?>

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