/* Program 2-12 Control LEDs using push-button switches.*/

const int LED[] = {5, 9, 10};
const int SW[] = {3, 4, 7};

void setup() {
    /* configure input output pins for switches and LEDs */
    for (int i = 0; i < 3; i++) {
        pinMode(LED[i], OUTPUT);
        pinMode(SW[i], INPUT);
    }
}

void loop()
{
    /* read switches and use the values to set LEDs */
    digitalGroupWrite(LED, 3, digitalGroupRead(SW, 3));
}

/* write to a group of output pins */
void digitalGroupWrite(const int* group, int length, int data) {
    for (int i = 0; i < length; i++)
        digitalWrite(group[i], data & (1 << i) ? HIGH : LOW);
}

/* read from a group of input pins */
int digitalGroupRead(const int* group, int length) {
    int data = 0;
    
    for (int i = 0; i < length; i++) {
        if (digitalRead(group[i])) {
            data |= 1 << i;
        }
    }
    return data;
}