I am trying to understand the example code about Encoding the states of DIP switch into number. I have already explaned everthing except the code they use for encode the binery to number.

 * This example code is in the public domain
 *
 * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-dip-switch
 */

#define POSITION_NUM 4[enter image description here](https://i.sstatic.net/82z3qGwT.png)
#define ON LOW
#define OFF HIGH

// define the pins connected to the dip switch
const int SWITCH_PINS[] = { 2, 3, 4, 5 };

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Set the DIP switch pins as inputs with pull-up resistors enabled
  for (int i = 0; i < POSITION_NUM; i++)
    pinMode(SWITCH_PINS[i], INPUT_PULLUP);
}

void loop() {
  int encoded_state = 0;
  for (int i = 0; i < POSITION_NUM; i++) {
    int state = digitalRead(SWITCH_PINS[i]);

    if (state == ON)
      encoded_state |= 1 << (POSITION_NUM - i - 1);
  }

I expect you guys could give me explaination about these problems. It would be ideal to consist of the code function because I have dove into many websites without getting any results. I appreciate it.