데이터 구조 - 체인 큐 (linked queue)

/* linkedQueue.c */
/*     */

#include 
#include 
#include 

/*         */
typedef struct node {
    int data;            /*        */
    struct node *next;  /*            */
} Node;
/* front     ，rear      */
/* front->next          */
typedef struct {
    Node *front, *rear;    
} Queue;

void interface(void);
/*         */
Queue *initializeQueue();
bool isEmptyQueue(Queue *q);
void inQueue(Queue *q, int number);
int outQueue(Queue *q);

int main(){
    Queue *q = initializeQueue();
    int flag, number;

    interface();
    for(;;){
        printf("Command: ");
        scanf("%d", &flag);
        switch(flag){
            case 0: puts("Bye!"); return 0; break;
            case 1:
                printf("Enter a number: ");
                scanf("%d", &number);
                inQueue(q, number);
                break;
            case 2:
                if(isEmptyQueue(q))
                    printf("Queue is empty!
");
                else
                    printf("value: %d
", outQueue(q));
                break;
        }
    }

    return 0;
}

void interface(void){
    puts("+************************+");
    puts("+  0, quit             +");
    puts("+  1, in               +");
    puts("+  2, out              +");
    puts("+************************+");
}
/*         */
/*        */
Queue *initializeQueue(){
    /*   Queue     Node   ，front rear       */
    Queue *q = (Queue*)malloc(sizeof(Queue));
    Node *p = (Node*)malloc(sizeof(Node));
    p->next = NULL;
    q->front = p;
    q->rear = p;
    return q;
}
/*          */
bool isEmptyQueue(Queue *q){
    if(q->front==q->rear)
        return true;
    else
        return false;
}
/*    */
void inQueue(Queue *q, int number){
    /*       ，  number  ，rear      */
    Node *p = (Node*)malloc(sizeof(Node));
    p->data = number;
    p->next = NULL;
    q->rear->next = p;        /*            next         */
    q->rear = p;            /* rear      */
}
/*    */
int outQueue(Queue *q){
    Node *p = q->front->next;    /* p           */
    q->front->next = p->next;    /* q->front->next        */
    int r = p->data;            /*             */
    free(p);                    /*         */
    /*        ，     ，        */
    if(q->front->next==NULL)
        q->rear = q->front;
    return r;
}