lights.ino

#include <Arduino.h>

struct State {
    int previous;
    int current;
};

class Button {
public:
    explicit Button(int);

    int pin;
    State state{};

    bool pressed();
};

Button::Button(int p) {
    pin = p;
    state = State{1, 1};
}

bool Button::pressed() {
    state.previous = state.current;
    state.current = digitalRead(pin);

    return ((state.current == 0) && (state.previous != state.current));
}

struct Light {
    int pin;
};

class LightSeries {
public:
    explicit LightSeries(Light[]);

    Light lights[3]{};
    int lightIndex;

    void cycle();
};

LightSeries::LightSeries(Light *l) {
    memcpy(lights, l, 3 * sizeof(Light));

    lightIndex = -1;
}

void LightSeries::cycle() {
    for (Light light : lights) {
        digitalWrite(light.pin, LOW);
    }

    lightIndex++;

    if (lightIndex < 3) {
        digitalWrite(lights[lightIndex].pin, HIGH);
    } else {
        lightIndex = -1;
    }
}

Light green{9};
Light yellow{10};
Light red{11};

Button button = Button(5);
Light lights[]{green, yellow, red};
LightSeries lightSeries = LightSeries(lights);

void setup() {
    for (Light light : lightSeries.lights) {
        pinMode(light.pin, OUTPUT);
        digitalWrite(light.pin, LOW);
    }

    pinMode(button.pin, INPUT);
    Serial.begin(9600);
}

void loop() {
    if (button.pressed()) {
        lightSeries.cycle();
    }
}