//queueTest.c
//John T. Rine
//October 29, 2011

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

struct Queue
{
	char *queueArray;
	int count;
	int size;
	int startIndex;
};

typedef  struct Queue queue;


void createQueue(queue *, int);
void destroyQueue(queue *);
void enqueue(queue *, char);
void printQueue(queue *);
int queueCount(queue *);
char dequeue(queue *);

int main(int argc, char **argv)
{
	queue newQueue;
	
	createQueue(&newQueue, 25);
	destroyQueue(&newQueue);
	enqueue(&newQueue, 'J');
        enqueue(&newQueue, 'o');
        enqueue(&newQueue, 'h');
        enqueue(&newQueue, 'n');
	printf("Calling printQueue(&newQueue)...\n");
        printQueue(&newQueue);
	printf("Calling and printing return value from dequeue...\n");
	printf("%c, ", dequeue(&newQueue));
        printf("%c, ", dequeue(&newQueue));
	printf("\n");
	printf("Calling printQueue(&newQueue)...\n");
	printQueue(&newQueue);

	return 0;
}

void createQueue(queue *queuePTR, int size)
{
	char *queueArrayPTR = NULL;
	queueArrayPTR = (char *)malloc(sizeof(char) * size);
	queuePTR->queueArray = queueArrayPTR;
	queuePTR->size = size;
	queuePTR->count = 0;
	queuePTR->startIndex = 0;
}

void destroyQueue(queue *queuePTR)
{
	free(queuePTR->queueArray);
}

void enqueue(queue *queuePTR, char data)
{
	int queueArrayIndex;
	if(queuePTR->count < queuePTR->size)
	{
		queueArrayIndex = queuePTR->startIndex + queuePTR->count;
		queuePTR->queueArray[queueArrayIndex] = data;
		queuePTR->count++;
	}
	else printf("Queue is full!\n");  
}

void printQueue(queue *queuePTR)
{
	int i;
	for(i = 0; i < queuePTR->count; i++) printf("%c, ",queuePTR->queueArray[(queuePTR->startIndex + i)%queuePTR->size]);
	printf("\n");
}


int queueCount(queue *queuePTR)
{
	return queuePTR->count;
}

char dequeue(queue *queuePTR)
{
	char ret;
	if(queuePTR->count == 0)
	{
		 printf("queue is empty!\n");
		exit(1);
	}
	ret = queuePTR->queueArray[queuePTR->startIndex];
    	queuePTR->count--;
    	queuePTR->startIndex = (queuePTR->startIndex + 1)%queuePTR->size;
    	return ret;
}