This is about the problem.

Where is this problem?

 
  Function Jisuan (& $a,& $b) {
$c = $a + $b;
Echo ' a+b= '. $c. "
";
}
if (Isset ($_post[' C ')) && isset ($_post[' d '))
{
$x =$_post[' C '];
$y =$_post[' d '];
Jisuan ($x, $y);
}

echo "Result is 0! ";
?>

Always hint that C and D are not defined. What's the reason?

------Solution--------------------
It's normal, not a mistake you said.
------Solution--------------------
No errors were found. Please post the code and error messages in full.
------Solution--------------------
The program is normal.
------Solution--------------------

 
      Function Jisuan (& $a,& $b) {
        $c = $a + $b;
        Echo ' a+b= '. $c. "
";
    }
    if (Isset ($_post[' C ')) && isset ($_post[' d '))
        {
            $x =$_post[' C '];
            $y =$_post[' d '];
            Jisuan ($x, $y);
        }
    
        echo "Result is 0! ";
?>

Create a new index.php file cut the above file inside, run the HTML page
------Solution--------------------
Reference:

Quote: Reference:

Notice can be set to ignore, without affecting the running

How do I set it?

error_reporting (0);

