priority queue

#include<stdio.h>

#include<conio.h>

#define MAX 5

struct queue

{

      int a[5];

      int rear,front;

}

st;

void enqueue(int x);

void dequeue();

void display();

void main()

{

      int op,x;

      st.rear=st.front=-1;

      do

      {

            printf("n1.Insertion\n2.Deletion\n3.Print\n4.Exit");

            printf("\nEnter choice=");

            scanf("%d",&op);

            switch(op)

            {

                  case 1:if((st.rear+1)%MAX==st.front)

                  printf("\nQueue is full");

                  else

                  enqueue(x);

                  break;

                  case 2:if(st.front==-1)

                  printf("\nEmpty queue");

                  else

                  {

                        dequeue();

                  }

                  break;

                  case 3:display();

                  break;

            }

      }while(op!=4);

      getch();

}

void enqueue(int x)

{

      int i;

      printf("\nEnter data:");

      scanf("%d",&x);

      if(st.rear==-1)

      {

            st.rear++;

            st.front++;

            st.a[st.rear]=x;

      }

      else

      {

            i=st.rear;

            while(x>st.a[i])

            {

                  st.a[(i+1)%MAX]=st.a[i];

                  i=(i-1+MAX)%MAX;

                  if((i-1)%MAX==st.front)

                  break;

            }

            i=(i+1)%MAX;

            st.a[i]=x;

            st.rear=(st.rear+1)%MAX;

      }

}

void dequeue()

{

      int y;

      if(st.rear==st.front)

      {

            y=st.a[st.front];

            st.front=-1;

            st.rear=-1;

      }

      else

      {

            y=st.a[st.front];

            st.front=(st.front+1)%MAX;

      }

      printf("\nDeleted element=%d",y);

}

void display()

{

      int i;

      if(st.rear==-1)

      printf("\nEmpty queue");

      else

      {

            printf("\nQueue is:");

            i=st.front;

            while(i!=st.rear)

            {

                  printf("<%d>",st.a[i]);

                  i=(i+1)%MAX;

            }

            printf("<%d>",st.a[st.rear]);

      }

}