John Davidson

Message:

I need to check in which flags a certain decimal variable $decimal = 3660 is included. I´ve set up the flags with hexadecimal constants. After that the function "show_flags" should output every flag where the decimal variable "3660" is included.

I don´t have much experience with bit flags and tried it like that, but I dont get any output. This is the demo.

Code

$decimal= 3660;



const FLAG_1 = 0x1;

const FLAG_2 = 0x2; 

const FLAG_3 = 0x4;

const FLAG_4 = 0x8; 

const FLAG_5 = 0x10; 

const FLAG_6 = 0x20; 

const FLAG_7 = 0x40;

const FLAG_8 = 0x80; 

const FLAG_9 = 0x100; 

const FLAG_10 = 0x200; 

const FLAG_11 = 0x400;  

const FLAG_12 = 0x800;  



function show_flags ($decimal) {

  if ($decimal & FLAG_1) {

    echo "Flag 1 included.<br>\n";

  }

  if ($decimal & FLAG_2) {

    echo "Flag 2 included.<br>\n";

  }

  if ($decimal & FLAG_3) {

    echo "Flag 3 included.<br>\n";

  }

  if ($decimal & FLAG_4) {

    echo "Flag 4 included.<br>\n";

  }

  if ($decimal & FLAG_5) {

    echo "Flag 5 included.<br>\n";

  }

  if ($decimal & FLAG_6) {

    echo "Flag 6 included.<br>\n";

  }

  if ($decimal & FLAG_7) {

    echo "Flag 7 included.<br>\n";

  }

  if ($decimal & FLAG_8) {

    echo "Flag 8 included.<br>\n";

  }

  if ($decimal & FLAG_9) {

    echo "Flag 9 included.<br>\n";

  }

  if ($decimal & FLAG_10) {

    echo "Flag 10 included.<br>\n";

  }

  if ($decimal & FLAG_11) {

    echo "Flag 11 included.<br>\n";

  }

  if ($decimal & FLAG_12) {

    echo "Flag 12 included.<br>\n";

  }

}

---

My Answer:
can be used to check if the decimal number includes a certain flag.

Here is an example code snippet to achieve this:

php
// Define hexadecimal constants for flags
define('FLAG_A', 0x01); // 0001
define('FLAG_B', 0x02); // 0010
define('FLAG_C', 0x04); // 0100
define('FLAG_D', 0x08); // 1000

// Decimal number to check
$decimal = 3660;

// Check if decimal number includes FLAG_A
if ($decimal & FLAG_A) {
echo "FLAG_A is included in the decimal number\n";
}

// Check if decimal number includes FLAG_B
if ($decimal & FLAG_B) {
echo "FLAG_B is included in the decimal number\n";
}

// Check if decimal number includes FLAG_C
if ($decimal & FLAG_C) {
echo "FLAG_C is included in the decimal number\n";
}

// Check if decimal number includes FLAG_D
if ($decimal & FLAG_D) {
echo "FLAG_D is included in the decimal number\n";
}


In this code snippet, we define hexadecimal constants for each flag (FLAG_A, FLAG_B, FLAG_C, FLAG_D) and then use bitwise AND operator (&) to check if the decimal number includes a certain flag. If the result of the bitwise AND operation is non-zero, it means that the flag is included in the decimal number.

You can add more flags and check for their inclusion in the decimal number using the same approach.