LINKED QUEUE IN PUSH, POP & PEEK OPERATIONS

CODING:
#include<stdio.h>
#include<conio.h>
struct node
{
 int data;
 struct node *next;
};
struct queue
{
 struct node *front;
 struct node *rear;
};
struct queue *q;
void create_queue(struct queue *);
struct queue *insert(struct queue *);
struct queue *delete_element(struct queue *);
struct queue *display(struct queue *);
int peek(struct queue *);
void main()
{
int ch,num;
clrscr();
create_queue(q);
do
 {
  printf("\nS E L E C T  C H O I C E");
  printf("\n1.INSERT");
  printf("\n2.DELETE");
  printf("\n3.PEEK");
  printf("\n4.DISPLAY");
  printf("\n5.EXIT");
  printf("\nEnter the Number:");
  scanf("%d",&ch);
  switch(ch)
   {
   case 1:
   q=insert(q);
   break;
   case 2:
   q=delete_element(q);
   break;
   case 3:
   num=peek(q);
   printf("%d is stored at the top of Queue.",num);
   break;
   case 4:
   q=display(q);
   break;
   case 5:
   exit(0);
   break;
   default:
   printf("Invalid Enter the number,TRY AGAIN.");
   break;
   }
 }while(ch!=5);
getch();
}
void create_queue(struct queue *q)
{
q->front=NULL;
q->rear=NULL;
}
struct queue *insert(struct queue *q)
{
int num;
struct node *ptr;
printf("Enter the number to be inserted in the Queue:");
scanf("%d",&num);
ptr=(struct node *)malloc(sizeof(struct node *));
ptr->data=num;
if(q->front==NULL)
 {
 q->front=ptr;
 q->rear=ptr;
 q->front->next=q->rear->next=NULL;
 }
else
 {
 q->rear->next=ptr;
 q->rear=ptr;
 q->rear->next=NULL;
 }
 return q;
}
struct queue *delete_element(struct queue *q)
{
struct node *ptr;
ptr=q->front;
if(q->front==NULL)
 printf("Queue is underflow.");
else
 {
 q->front=q->front->next;
 printf("%d is deleted in Queue.",ptr->data);
 free(ptr);
 }
 return q;
}
struct queue *display(struct queue *q)
{
struct node *ptr;
ptr=q->front;
if(ptr==NULL)
 printf("Queue is Empty.");
else
 {
printf("QUEUE:\n");
while(ptr!=q->rear)
  {
  printf("%d\n",ptr->data);
  ptr=ptr->next;
  }
  printf("%d",ptr->data);
 }
 return q;
}
int peek(struct queue *q)
{
 return q->front->data;
}