queue

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

struct node
{
    int data;
    struct node *next;
}*front,*front1,*rear,*temp;
void enq(int data)
{
    if(rear == NULL)
    {
        rear = (struct node*)malloc(sizeof(struct node));

        rear->data = data;
        rear->next = NULL;
        front = rear;
    }
    else
    {
        temp = (struct node*)malloc(sizeof(struct node));

        rear->next = temp;
        temp->data = data;
        temp->next = NULL;

        rear = temp;
    }
}
void deq()
{
    front1 = front;

    if(front1 == NULL)
        printf("Your queue is empty\n");
    else
    {
        if(front1->next != NULL)
        {
            front1 = front1->next;
            printf("Dequeued value %d\n",front->data);
            free(front);
            front = front1;
        }
        else
        {
            printf("Dequeued value %d\n",front->data);
            free(front);
            front = NULL;
            rear = NULL;
        }
    }
}
void display()
{
    front1 = front;
    if(front1 == NULL && rear == NULL)
        printf("Queue is empty\n");

    while(front1 != rear)
    {
        printf("%d\n",front1->data);
        front1 = front1->next;
    }
    printf("%d\n",front1->data);
}

int main()
{
    front = rear = NULL;
    enq(10);
    enq(20);
    enq(30);
    printf("Queue before dequeue:\n");
    display();
    deq();
    printf("Queue after dequeue:\n");
    display();
}