Priority Queue with heap in C

//Priority Queue with heap:


#include<stdio.h>
#include<malloc.h>
void insert();
void del();
void display();

struct node
{
int priority;
int info;
struct node *next;
}*start=NULL,*q,*temp,*new;


typedef struct node N;
int main()
{
int ch;
clrscr();
do
{
printf("\n[1] INSERTION\t[2] DELETION\t[3] DISPLAY [4] EXIT\t:");
scanf("%d",&ch);
switch(ch)
{
case 1:insert();
break;
case 2:del();
break;
case 3:display();
break;
case 4:
break;
}
}
while(ch<4);
}

void insert()
{
int item,itprio;
new=(N*)malloc(sizeof(N));
printf("ENTER THE ELT.TO BE INSERTED :\t");
scanf("%d",&item);
printf("ENTER ITS PRIORITY :\t");
scanf("%d",&itprio);
new->info=item;
new->priority=itprio;
new->next=NULL;
if(start==NULL )
{
//new->next=start;
start=new;
}
else if(start!=NULL&&itprio<=start->priority)
{  new->next=start;
start=new;
}
else
{
q=start;
while(q->next != NULL && q->next->priority<=itprio)
{q=q->next;}
new->next=q->next;
q->next=new;
}
}

void del()
{
if(start==NULL)
{
printf("\nQUEUE UNDERFLOW\n");

}
else
{
new=start;
printf("\nDELETED ITEM IS %d\n",new->info);
start=start->next;
//free(start);
}
}

void display()
{
temp=start;
if(start==NULL)
printf("QUEUE IS EMPTY\n");
else
{
printf("QUEUE IS:\n");
if(temp!=NULL)
for(temp=start;temp!=NULL;temp=temp->next)
{
printf("\n%d priority =%d\n",temp->info,temp->priority);
//temp=temp->next;
}
}
}