SLL QUEUE

#include <stdio.h>
#include <stdlib.h>

#define TYPE int

typedef struct Node{
    TYPE data;
    struct Node *next;
}Node;

typedef struct Queue{
    Node *head,*tail;
    int numberOfElements;
}Queue;

void reset(Queue *q);
int isEmpty(Queue *q);
void enqueue(Queue *q,TYPE val);
TYPE dequeue(Queue *q);
void display(Queue q);

int main(){
    system("clear");
    Queue q; reset(&q);
    enqueue(&q,1); enqueue(&q,2);
    enqueue(&q,4); enqueue(&q,5);
    enqueue(&q,3); enqueue(&q,6);

    dequeue(&q);
    dequeue(&q);dequeue(&q);
    dequeue(&q);dequeue(&q);
    dequeue(&q);dequeue(&q);

    enqueue(&q,1);enqueue(&q,3);

    display(q);
    return 0;
}

void reset(Queue *q){ q->head = q->tail = NULL; q->numberOfElements =  0; }
int isEmpty(Queue *q){ return q->numberOfElements == 0; }

void enqueue(Queue *q,TYPE val){
    Node * node = (Node*) malloc(sizeof(Node));
    node->data = val;
    node->next = NULL;

    isEmpty(q) ? (q->tail = node) : (q->head->next = node);

    q->head = node;
    q->numberOfElements++;
}

TYPE dequeue(Queue *q){
    if(!isEmpty(q)) {
        TYPE x = q->tail->data;
        Node *tmp = q->tail;
        if(!q->tail->next)
            reset(q);
        else{
            free(q->tail);
            q->tail = tmp->next;
        }
        q->numberOfElements--;
        return x;
    }
    return 1<<31;
}

void display(Queue q){ while(!isEmpty(&q)) printf("[%d]\n", dequeue(&q)); }