Help with coding arduino uno + smart rich shield

Projects Programming
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// check multiple buttons and toggle LEDs

enum { Off = HIGH, On = LOW };

byte pinsLed [] = { 10, 11, 12 };
byte pinsBut [] = { A1, A2, A3 };
#define N_BUT   sizeof(pinsBut)

byte butState [N_BUT];

#define MAX_DIGIT  5
byte code  [] = { 1, 2, 3, 4 };
#define N_DIGIT     sizeof(code)

byte combo [N_DIGIT] = {};
byte digit           = 0;

char s [40];

// -----------------------------------------------------------------------------
void
dispCombo (void)
{
    for (unsigned n = 0; n < N_DIGIT; n++)
        Serial.print (combo [n]);
    Serial.println ();
}

// -----------------------------------------------------------------------------
void
jumble (void)
{
    for (unsigned n = 0; n < N_DIGIT; n++)
        combo [n] = random (0, MAX_DIGIT-1);
    dispCombo ();
}

// -----------------------------------------------------------------------------
bool
unlocked (void)
{
    for (unsigned n = 0; n < N_DIGIT; n++)
        if (code [n] != combo [n])
            return false;
    return true;
}

// -----------------------------------------------------------------------------
enum {
    ButInc,
    ButNext,
    Door,

    ButIncRel  = 10 + ButInc,
    ButNextRel = 10 + ButNext,
    DoorClosed = 10 + Door
};

int
chkButtons ()
{
    for (unsigned n = 0; n < sizeof(pinsBut); n++)  {
        byte but = digitalRead (pinsBut [n]);

        if (butState [n] != but)  {
            butState [n] = but;

            delay (10);     // debounce

            if (On == but)
                return n;
            else
                return 10 + n;
        }
    }
    return -1;
}

// -----------------------------------------------------------------------------
void
loop ()
{
    switch (chkButtons ())  {
    case DoorClosed:
        jumble ();
        break;

    case Door:
        if (unlocked ())
            Serial.println ("door");
        else
            Serial.println ("alarm");
        break;

    case ButNext:
        digit = (digit + 1) % N_DIGIT;
        break;

    case ButInc:
        combo [digit] = (combo [digit] + 1) % MAX_DIGIT;
        dispCombo ();
        break;
    }
}

// -----------------------------------------------------------------------------
void
setup ()
{
    Serial.begin (9600);

    for (unsigned n = 0; n < sizeof(pinsBut); n++)  {
        pinMode (pinsBut [n], INPUT_PULLUP);
        butState [n] = digitalRead (pinsBut [n]);
    }

    for (unsigned n = 0; n < sizeof(pinsLed); n++)  {
        digitalWrite (pinsLed [n], Off);
        pinMode      (pinsLed [n], OUTPUT);
    }

    dispCombo ();
}