// Function to initialize the LED pins and button pin.
void initializePins() {
    // Set LED pins as OUTPUT.
    pinMode(13, OUTPUT);
    pinMode(12, OUTPUT);
    pinMode(11, OUTPUT);
    pinMode(10, OUTPUT);
    pinMode(9, OUTPUT);

    // Set button pin as INPUT.
    pinMode(2, INPUT);
}

// Function to turn on the LEDs based on the button press using switch case.
void turnOnLEDs() {
    // Read the state of the button.
    int buttonState = digitalRead(2);

    // Use switch case to determine which LED to turn on based on the button state.
    switch (buttonState) {
        case HIGH:
            digitalWrite(13, HIGH);
            digitalWrite(12, HIGH);
            digitalWrite(11, HIGH);
            digitalWrite(10, HIGH);
            digitalWrite(9, HIGH);
            break;
        case LOW:
            digitalWrite(13, LOW);
            digitalWrite(12, LOW);
            digitalWrite(11, LOW);
            digitalWrite(10, LOW);
            digitalWrite(9, LOW);
            break;
    }
}

void setup() {
    // Call the function to initialize the pins.
    initializePins();
}

void loop() {
    // Call the function to turn on the LEDs based on the button press.
    turnOnLEDs();
}