Question

Consider the following structure definitions and fill in the blanks for the enqueue function:

    typedef struct queue queue_t;
    typedef struct node node_t;

    struct node {
        node_t *next;
         void *val; };

    struct queue {
        node_t *head;
        node_t *tail;};

/* add val at the tail of the queue q */

void enqueue (queue_t *q, void *val) {
    if (q->head == NULL) {

        _______________ = _______________ = malloc(sizeof(_______________));

        _______________ = NULL;
    } else {

        _______________ = _______________ = malloc(sizeof(_______________));

        _______________ = NULL;
    }

    q->tail->val = val;
}

Answer 1

typedef struct queue queue_t;
    typedef struct node node_t;

    struct node {
        node_t *next;
         void *val; };

    struct queue {
        node_t *head;
        node_t *tail;};

/* add val at the tail of the queue q */

void enqueue (queue_t *q, void *val) {
    if (q->head == NULL) {

        q->head = q->tail = malloc(sizeof(struct node));

        q->head->next = NULL;
    } else {

        q->tail = q->tail->next = malloc(sizeof(struct node));

        q->tail->next = NULL;
    }

    q->tail->val = val;
}