선형큐

#include<stdio.h>
#include<stdlib.h>
#define MAX_QUEUE_SIZE 100

int data[MAX_QUEUE_SIZE];
int front;
int rear;

void init_queue() { front = rear = 0; }
int is_empty() { return front == rear; }
int is_full() { return front == (rear + 1) % MAX_QUEUE_SIZE; }
int size() { return (rear - front + MAX_QUEUE_SIZE) % MAX_QUEUE_SIZE; }

void enqueue(int val) {
	if (!is_full()) {
		rear = (rear + 1) % MAX_QUEUE_SIZE;
		data[rear] = val;
	}
}

int dequeue() {
	if (!is_empty()) {
		front = (front + 1) % MAX_QUEUE_SIZE;
		return data[front];
	}
}

int peek() {
	if (!is_empty()) {
		return data[(front + 1) % MAX_QUEUE_SIZE];
	}
}

void print_queue(char msg[]) {
	int i, maxi = rear;
	if (front >= rear) maxi += MAX_QUEUE_SIZE;
	printf("%s[%2d]= ", msg, size());
	for (i = front + 1; i <= maxi; i++) {
		printf("%2d ", data[i % MAX_QUEUE_SIZE]);
	}
	printf("\n");
}

void main() {
	int i;
	init_queue();
	for (int i = 1; i < 10; i++) {
		enqueue(i);
	}
	print_queue("선형큐 equeue 9회");
	printf("\tdequeue() --> %d\n", dequeue());
	printf("\tdequeue() --> %d\n", dequeue());
	printf("\tdequeue() --> %d\n", dequeue());
	print_queue("선형큐 equeue 3회");
}