traffic light state machine example

traffic_machine.c

#include <stdio.h>

enum TrafficLightState {
    RED,
    GREEN,
    YELLOW
};

void transition(enum TrafficLightState *state) {
    switch (*state) {
        case RED:
            *state = GREEN;
            break;
        case GREEN:
            *state = YELLOW;
            break;
        case YELLOW:
            *state = RED;
            break;
    }
}

int main() {
    enum TrafficLightState currentState = RED;

    while (1) {
        switch (currentState) {
            case RED:
                printf("Red light\n");
                break;
            case GREEN:
                printf("Green light\n");
                break;
            case YELLOW:
                printf("Yellow light\n");
                break;
        }
        // simulate a timer or event triggering state transition
        transition(&currentState);
    }

    return 0;
}