Pick a random number and display it on the 7-segment display

random_number.c

int A = 7;
int B = 8;
int C = 9;
int D = 10;
int E = 11;
int F = 12;
int G = 13;

byte digits[] = {126, 48, 109, 121, 51,
                 91, 95, 112, 127, 115};

void setup(void)
{
    pinMode(2, INPUT_PULLUP);
    randomSeed(analogRead(A0));
    for (int i = A; i <= G; i++)
    {
        pinMode(i, OUTPUT);
    }
}

int n = 0;
int button;
int last_button;
void loop()
{
    // This is our button pressing code from before
    last_button = button;
    button = digitalRead(2);
    if (button == LOW && last_button == HIGH)
    {
        n = random(1, 6);
    }

    // Displays the digit "n" on the 7-segment display
    byte mask = 64;
    for (int segment = A; segment <= G; segment++)
    {
        digitalWrite(segment, digits[n] & mask);
        mask = mask >> 1;
    }
    delay(10);
}