#include #define SIZE 3 typedef struct { int a[SIZE]; int front; int rear;} Queue; void enq(Queue* q, int val){ q->a[q->rear] = val; q->rear = (q->rear + 1) % SIZE;} int deq(Queue* q) { int val = q->a[q->front]; q->front = (q->front + 1) % SIZE; return val;} int main() { Queue q = {{0}, 0, 0}; enq(&q,1); enq(&q,2); deq(&q); enq(&q, 3); int first = deq(&q); ..