How to make a function where every time a variable is called is increased by 1?

Question

For example,

amid my code I do

echo $num;  //me retorna 1, mas se eu ecoar novamente a variável "$num" 
            //me retornará 2   e assim sucessivamente.

I tried a lot of different ways, but I couldn’t:

function add_um(){  
}

add_um(); //Nesse caso toda vez que eu chamasse a função ela
//me traria um número diferente do anterior, sempre acrescentando 1 unidade.

I tried with while, but fell into an infinite loop 1234567...

ADDED:

It is possible to use the $num to name a session? type, $_SESSÃO[$num]; and then nominate another session hypothetically like this: $_SESSÃO[$num++]; ?

That’s what I needed. Automatically naming sessions.

I thought of using the for to create a $i that would increase(i++) each loop to name the sessions, but I’m already working within a for and then the loops would keep repeating.

Answer 1

Another possibility would be using magical methods.

_example

$counter = new Counter();
echo $counter;
echo $counter;
echo $counter;

echo $counter, $counter, $counter;

_output

123

_class

class Counter
{
    public static $counter = 0;

    public function __toString()
    {
        static::$counter++;
        return (string) static::$counter;
    }
}

---

Whenever you give echo in a variable containing the object, the ++ incrementer of the method will be executed __toString.

_PHP

The __toString() method allows a class to decide how to behave when converted to a string. For example, what echo $obj; will print. This method needs to return a string, but an E_RECOVERABLE_ERROR error is generated.

Answer 2

To do this in a variable:

$num = 0;
echo $num++ ;
echo $num++ ;
echo $num++ ;
echo $num++ ;

Using passage by reference:

function add_um( &$num ){  
   $num++;
}

$num = 0;
add_um( $num );
echo $num;
add_um( $num );
echo $num;
add_um( $num );
echo $num;

or even

function add_um( &$num ){  
   $num++;
   echo $num;
}

$num = 0;
add_um( $num );
add_um( $num );
add_um( $num );

Using global (do not recommend):

function add_um(){  
   global $num;
   $num++;
}

$num = 0;
add_um();

The global was a generic example, there are a thousand ways to do this.

Answer 3

There are two simple ways to do this, and with slightly different results, see which one fits your need best:

$num = 1;

echo $num++ . '<br>'; // retorna o valor atual da variável (que é 1) e soma + 1 (fica 2)

echo $num++ . '<br>'; // retorna o valor atual da variável (agora é 2) e soma + 1 (fica 3)

echo $num++ . '<br>'; // retorna o valor atual da variável (agora é 3) e soma + 1 (fica 4)

// e assim sucessivamente...

// retorno:
1
2
3

// ou desta forma:
$num = 1;

echo ($num += 1) . '<br>'; // Soma + 1 e retorna o novo valor da variável (que fica 2)

echo ($num += 1) . '<br>'; // Soma + 1 e retorna o novo valor da variável (que fica 3) 

echo ($num += 1) . '<br>'; // Soma + 1 e retorna o novo valor da variável (que fica 4)

// retorno:
2
3
4

For each page request, the counter sum 1, just do so:

session_start();

if (!isset($_SESSION['num'])) $_SESSION['num'] = 0;

$num =& $_SESSION['num'];

echo $num++;

Remembering that this is per session, that is, each user will have an independent counter while their session is alive...