编程，使用全局变量的逻辑

lets say i have a function add().

function add(){
 if (a)
  return true;
 if (b)
  return true;
 if (c)
  insert into table. 
  return true;
 }

now i call this function add() and i want to increment my counter only if there is insert execution like condition C. I also don't want to change the return value which is true. Now my question is how can i find out if section C is executed? I thought i can use a global variable in condition c like below

if (c)
{
 insert into table. 
 $added = true;
 return true;
}

and then i check

if(isset($added && $added==true))
$count++;

but i would like to know if there is any parameter i can add or some other approach i can use?

Add an if around your insert, and add a counter as a parameter:

$count = 0;
function add(&$count){
 if (a)
  return true;
 if (b)
  return true;
 if (c)
  if(insert into table){ //Queries return a boolean
    $count++;
  } 
  return true;
}

add($count); //If insertion was succesful it added 1 to counter.
echo $count; //Returns either 1 or 0 depending on insert statement.

You can pass a parameter by reference. In PHP, this is done by prepending a pound sign (&). The result is that your function doesn't get a copy of the value but a variable refering the original value, so you can change it inside your function.

function add(&$itemsAdded)
{
    $itemsAdded = 0;
    [...]
    /* if added something */
    $itemsAdded++;
}

in your calling code

add($added);
$counter += $added;