Queue error in main

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

struct Node{
    int data;
    struct Node *next;
}*node,*temp;

struct Head{
    int count;
    struct Node *front,*rear;
}*head;

void create_queue()
{
    head=(struct Head*)malloc(sizeof(struct Head));
    head->count=0;
    head->front=NULL;
    head->rear=NULL;
}
void first_node()
{
    node=(struct Node*)malloc(sizeof(struct Node));
    printf("Plz input data in QueUe\n");
    scanf("%d",&node->data);
    node->next=NULL;
    head->front=node;
    head->rear=node;
    head->count++;
}

void Enqueue()
{
    node=(struct Node*)malloc(sizeof(struct Node));
    printf("Plz input data in QueUe\n");
    scanf("%d",&node->data);
    node->next=NULL;
    head->rear->next=node;
    head->rear=node;
    head->count++;

}

void Dequeue()
{
    temp=head->front;
    head->front=temp->next;
     printf("%d is delated from Queue\n",temp->data);
    free(temp);
    head->count--;

}

void show()
{
    int i;
    temp=head->front;
    for( i=0;i<head->count;i++)
    {
        printf("%d",temp->data);
        temp=temp->next;
    }
}

int main()
{
    int i;

    while(1)
    {
    printf("Select ur Choice");
    printf("Press 1 to create queue");
    printf("Press 2 For Enqueue");
    printf("Press 3 For Dequeue");

        switch(i){

    case 1:
        {
            if(head->count==0){
                create_queue();
            }
            else
                printf("Al ready Queue is Created/Exist\n");
                break;
        }
    case 2:
        {
            if(head->count>=1){
                Enqueue();
            }
            else
                printf("First Create a queue\n");
                break;
        }

    case 3:
        {

        if(head->count>=1){
                Dequeue();
            }
            else
                printf("First Insert data in Queue\n");
                break;
        }
    default:
                printf("Wrong Choice.PLz select Right option\n");
                break;
        }
    }
}