Question

Lets say we have function that gets 5 variables.

function func($var1, $var2, $var3, $var4, $var5 ) 
{
  if ($var1==1)
  {
    work with $var2, $var3
  }
  if ($var1==2)
  {
    work with $var4, $var5
  }
}

For example, we want to call this function like that: func(1,$var2, $var3) (without unused variables) or like that func(2,$var4, $var5).

Is it possible? How to send exact variables to php function?

UPDATE
Based on @marcus’s answer I modified my function.

<?

function GenerateTopNav($current, $lang, $db)
{
    $result=$db->query("SELECT `id`, `parent`, $lang FROM `nav` WHERE `menu`='1'");
        while ($row=$result->fetch_object()){
            echo '<a ';
            if($row->id==$current)
            echo 'class="active"';
            echo 'href="index.php?id='.$row->id.'">'.$row->$lang.'</a> | ';
    }

function GenerateLeftNav($parent, $level, $lang, $db){  
         $q = $db->query("SELECT `id`, `$lang` AS name FROM nav WHERE parent = '$parent' AND `menu`='2'");
          if($level > 0 && $q->num_rows > 0){
          echo "\n<ul>\n";
          }
          while($row=$q->fetch_object()){
                echo "<li>";
                echo '<a href="?page=' . $row->id . '">' . $row->name . '</a>';
                //display this level's children
                GenerateLeftNav($row->id, $level+1, $lang, $db);
                echo "</li>\n\n";
            }
          if($level > 0 &&  $q->num_rows > 0){
                echo "</ul>\n";
            }
          }
}
?>

Answer 1

Why do you even need to specify 4 variables? You’re basically saying specify a type and then 2 input variables for that type, so if there will always be 3 variables, just do the follow:

function ($type, $var1, $var2) {
    if ($type === 1) {
        // $var1 = lang and $var2 = current
        // do something with var1 and var2
    } else {
        // $var1 = parent and $var2 = level
        // do something else with var1 and var2
    }
}

You really don’t need to spam your function with an excess number of variables that won’t get used.

To be more clear: the variables don’t need to be named appropriately, you just need to comment that if type = 1, these two variables mean these two things, and if type = 2, these two variables mean these two things and process both types accordingly.