Program - Priority Queue

Program - Priority Queue
// Priority queue

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

#define MAX 5

// Structure for data

struct data
{
  int val,p,o;
}d[MAX];

 int front=-1,rear=-1;

// Insert operation
void  insert(struct data d1)
{
   struct data temp;
   int i,j;

   if(rear==MAX-1)
  {
    printf("\n Priority Queue is Full...");
    getch();
  }
  else
  {
    rear++;
    d[rear]=d1;
    if(front==-1)
      front=0;
    for(i=front;i<=rear;i++) // arrange priority 
    {
      for(j=i+1;j<=rear;j++)
      {
if(d[i].p > d[j].p)
{
 temp=d[i];
 d[i]=d[j];
 d[j]=temp;
}
else
{
 if(d[i].p==d[j].p) // if two job has same priority
 {
   if(d[i].o > d[j].o) // arrange as per order from
   {
     temp=d[i];
     d[i]=d[j];
     d[j]=temp;
   }
 }
}
      }
    }
  }
}
// Delete operation
void  deletion()
{
  struct data d1;
  if(front==-1)
    printf("\n Priority Queue is Empty...");
  else
  {
    printf("-------------------------------\n");
    printf("\n Value:    %d",d[front].val);
    printf("\n Priority: %d",d[front].p);
    printf("\n Order:    %d",d[front].o);
    printf("\n -------------------------------");
    if(front==rear)
      front=rear=-1;
    else
      front++;
  }
}

// Display operation
void  display()
{
   int i;

  if(front==-1)
    printf("\n Priority Queue is Empty...");
  else
  {
    for(i=front;i<=rear;i++)
    {
      printf("\n -------------------------------");
      printf("\n Object :  %d",i+1);;
      printf("\n Value  :  %d",d[i].val);
      printf("\n Priority: %d",d[i].p);
      printf("\n Order  :  %d",d[i].o);
      printf("\n -------------------------------");
    }
  }
}

// main() section
void main()
{
  struct data d1;
  // Executable section
  do
  {
    int ch;
    clrscr();
    // Print menu
    printf("\n-------------------");
    printf("\n     M E N U             ");
    printf("\n-------------------");
    printf("\n1 Insertion");
    printf("\n2 Deletion");
    printf("\n3 Display");
    printf("\n4 Exit");
    printf("\n-------------------");
    printf("\nEnter Choice... ");
    scanf("%d",&ch);
    switch(ch)
    {
       // Insertion case
       case 1:
printf("\n\t\tEnter Value:- ");
scanf("%d",&d1.val);
printf("\n\t\tEnter Priority:- ");
scanf("%d",&d1.p);
printf("\n\t\tEnter Order:- ");
scanf("%d",&d1.o);
insert(d1);
break;
       // Deletion case
       case 2:
deletion();
getch();
break;
       // Display case
       case 3:
display();
getch();
break;
       // Exit case
       case 4:
exit(0);
       // Default case
       default:
printf("\nInvalid Choice...");
getch();
    }
  }while(1);

  getch();
}

Posted By : Ruchita Pandya