# Simulation of Queue using an Array

#include<conio.h>
#include<stdio.h>
#define MAX 5

typedef struct Q
{
int R,F;
int data[MAX];
}Q;

void initialise(Q *P);
int empty(Q *P);
int full(Q *P);
void enqueue(Q *P,int x);
int dequeue(Q *P);
void print(Q *P);
void main()
{
Q q;
int op,x;
initialise(&q);
clrscr();
do
{
printf("\n\n1)Insert\n2)Delete\n3)Print\n4)Quit");
scanf("%d",&op);
switch(op)
{
case 1: printf("\n Enter a value:");
scanf("%d",&x);
if(!full(&q))
enqueue(&q,x);
else
printf("\nQueue is full !!!!");
break;
case 2: if(!empty(&q))
{
x=dequeue(&q);
printf("\Deleted Data=%d",x);
}
else
printf("\nQueue is empty !!!!");
break;
case 3: print(&q);break;
}
}while(op!=4);
}

void initialise(Q *P)
{
P->R=-1;
P->F=-1;
}

int empty(Q *P)
{
if(P->R==-1)
return(1);
return(0);
}

int full(Q *P)
{
if(P->R==MAX-1)
return(1);
return(0);
}

void enqueue(Q *P,int x)
{
if(P->R==-1)
{
P->R=P->F=0;
P->data[P->R]=x;
}
else
{
P->R=P->R+1%MAX;
P->data[P->R]=x;
}
}

int dequeue(Q *P)
{
int x;
x=P->data[P->F];
if(P->R==P->F)
{
P->R=-1;
P->F=-1;
}
else
P->F=P->F+1;
return(x);
}

void print(Q *P)
{
int i;
if(!empty(P))
{
printf("\n");
for(i=P->F;i<=P->R;i++)
printf("%d\t",P->data[i]);
}
}