void add(queue *q, int x)
{
    node_pointer temp;
    temp = (queue)malloc(sizeof(struct queuenode));
    temp -> data = x;
    (*q) = temp -> next;
    (*q) = temp;

    if ((*q)==NULL)
    {
        (*q) -> front = temp;
        (*q) -> back = temp;
    }
    else
    {
        (*q) -> back -> next = temp;
        (*q) -> back = temp;
    }
}

typedef struct queuenode {
    int data;
    struct queuenode *next;
} *node_pointer;



typedef struct endpointer {
    node_pointer front;
    node_pointer back;
} *queue;