/*7. PROGRAM TO IMPLEMENT PRIORITY QUEUES*/
#include<stdio.h>
#include<conio.h>
#define size 5
int r1=-1,r2=-1,r3=-1;
int f1,f2,f3;
int q1[size],q2[size],q3[size];

void PQinsert(int item,int num)
   {
    switch(num)
     {
      case 1:
	   if(r1==size-1)
		printf("\nQ1 Overflow\n");
	   else
		q1[++r1]=item;
	   break;
      case 2:
	   if(r2==size-1)
		printf("\nQ2 Overflow\n");
	   else
		q2[++r2]=item;
	   break;
      case 3:
	   if(r3==size-1)
		printf("\nQ3 Overflow\n");
	   else
		q3[++r3]=item;
	   break;
      case 4:
	   exit(0);
      default :
	    printf("\nQ number should be b/w 1 to 3\n");
	 }
	 getch();
    }
void PQdelete()
    {
     if(r1==-1)
	printf("\nQ1 Underflow\n");
     else
      {
	printf("\nFrom Q1");
	printf("\nDeleted item is %d\n",q1[f1++]);
	if(f1>r1)
	  f1=0,r1=-1;
	return;
       }
     if(r2==-1)
	printf("\nQ2 Underflow\n");
     else
      {
	printf("\nFrom Q2");
	printf("\nDeleted item is %d\n",q2[f2++]);
	if(f2>r2)
	  f2=0,r2=-1;
	return;
       }
     if(r3==-1)
	printf("\nQ3 Underflow\n");
     else
      {
	printf("\nFrom Q3");
	printf("\nDeleted item is %d\n",q3[f3++]);
	if(f3>r3)
	  f3=0,r3=-1;
	return;
      }
   }
void display(int i,int f,int r,int q[])
   {
    int j;
    if(r==-1)
	printf("\nQ%d is empty",i);
    else
     {
     printf("\nQ%d contents are\n",i);
     for(j=f;j<=r;j++)
     printf("%d\t",q[j]);
     }
    }
void PQdisplay()
    {
    display(1,f1,r1,q1);
    display(2,f2,r2,q2);
    display(3,f3,r3,q3);
    }

void main()
    {
    int ch,item,num;
    for(;;)
     {
     clrscr();
     printf("\n1:INSERT\n2:DELETE\n3:DISPLAY\n4:Quit\n");
     printf("\nEnter ur choice\n");
     scanf("%d",&ch);
      switch(ch)
	 {
	  case 1:
		printf("\nEnter the Q element to be inserted\n");
		scanf("%d",&item);
		printf("\nEnter Q number\n");
		scanf("%d",&num);
		PQinsert(item,num);
		break;
	  case 2:
		PQdelete();
		break;
	  case 3:
		PQdisplay();
		break;
	  case 4:
		exit(0);
	  default :
		printf("Invalid choice\n");
	   }
		getch();
	}
      }