Queue Data Structure

Program for QUEUE Data Structure has been done , below is the program for

***************Prototype****************

int mainmenu();
typedef struct staack
{
int fp;
int rp;
int size;
int *stkptr;
}queue;
queue* creatqueue();
int enqueue(queue*);
int dequeue(queue*);
int display(queue*);

****************Createqueue*************

#include"headers.h"
#include"prototype.h"

queue* creatqueue()
{
queue *start;
start = (queue*)malloc(sizeof(queue));
printf("enter the size of queue\n");

scanf("%d",&start->size);

start->stkptr = (int*)malloc(sizeof(int)*start->size);
if(!start->stkptr)
{
perror("malloc");
exit(EXIT_FAILURE);
}
start->fp=-1;
start->rp=-1;

return start;
}


*****************Enqueue***************

#include"headers.h"
#include"prototype.h"

int enqueue(queue *start)

{
if(start->rp==start->size-1)
{
puts("stack is full now\n");
return 0;
}
start->rp++;

if(start->fp>=0)
{
if(start->rp==start->fp)
{
puts("stack is full now\n");
return 0;
}
}
if(start->fp>=0)
{
start->rp=0;
}
puts("enter value in the queue\n");
scanf("%d",(start->stkptr+start->rp));

}


****************Dequeue****************

#include"headers.h"
#include"prototype.h"

int dequeue(queue *start)
{
if(start->rp==-1)
{
puts("stack is empty now\n");
return 0;
}
start->fp++;

}

*****************Display*****************


#include"headers.h"
#include"prototype.h"

int display(queue *start)

{
int i,j;
j=start->rp;
for(i=start->rp; i>start->fp; i--)
{
if(start->fp>0)
{
start->rp=start->size-1;
printf("| %d >>-->> %d |\n",i,*(start->stkptr+i));
start->rp=j;
}

printf("| %d >>-->> %d |\n",i,*(start->stkptr+i));
}

}