Perform "Insert" and "Delete" on Priority Queue

Write a Program in C to Perform "Insert" and "Delete" on Priority Queue

#include<stdio.h>
#include<conio.h>
#include<malloc.h>
void insert(int num,int prio);
void display();
void del();
struct node
{
int priority;
int data;
struct node *addr_next;
}*front = NULL,*tmp,*q,*ptr;
void main()
{
char choice='y';
int action,n,prio;
clrscr();
while(1)
{
printf("1) Insert\n");
printf("2) Delete\n");
printf("3) Display\n");
printf("4) Exit\n");
printf("Enter your choice : ");
scanf("%d",&action);
switch(action)
{
case 1:
choice='y';
while(choice=='y'||choice=='Y')
{
printf("\nEnter a number and Priority : ");
scanf("%d %d",&n,&prio);
insert(n,prio);
printf("\n");
display();
printf("\t\t\t\t\t\t\t\tContinue ? ");
scanf(" %c",&choice);
}
getch();
break;
case 2:
choice='y';
while(choice=='y'||choice=='Y')
{
del();
printf("\n");
display();
printf("\t\t\t\t\t\t\t\tContinue ? ");
scanf(" %c",&choice);
}
getch();
break;
case 3:
display();
break;
case 4:
exit();
break;
}
}
}
void insert(int num,int prio)
{
tmp=(struct node *)malloc(sizeof(struct node));
tmp->data=num;
tmp->priority=prio;
if(front==NULL||prio<front->priority) // check queue is empty or item to be added has priority more than first one
{
tmp->addr_next=front;
front=tmp;
}
else
{
q=front;
while(q->addr_next!=NULL && q->addr_next->priority<=prio)
{
q=q->addr_next;
}
tmp->addr_next = q->addr_next;
q->addr_next = tmp;
}
}
void display()
{
ptr = front;
if(front == NULL)
{
printf("Queue is empty\n");
}
else
{
printf("Data \t Priority\n");
while(ptr != NULL)
{
printf("%d \t %d\n",ptr->data,ptr->priority);
ptr=ptr->addr_next;
}
}
}
void del()
{
if(front == NULL)
{
printf("Queue is empty\n");
}
else
{

tmp=front;

front = front->addr_next;
free(tmp);
}
}