队列的数组实现
queen.h:
#include <stdlib.h>
#define QUEUE_TYPE char
void insert(QUEUE_TYPE value);
void delete();
QUEUE_TYPE first();
int is_empty();
int is_full();
queen.c:
#include "queen.h"
#include <stdio.h>
#include <assert.h>
#define QUEUE_SIZE 5
/*
** 使用不完全填满数组的技巧，不好理解
*/
/*
#define ARRAY_SIZE (QUEUE_SIZE + 1)
static QUEUE_TYPE queue[ARRAY_SIZE];
static size_t front = 1;
static size_t rear = 0;
void insert(QUEUE_TYPE value)
{
assert(!is_full());
rear = (rear + 1) % ARRAY_SIZE;
queue[rear] = value;
}
void delete()
{
assert(!is_empty());
front = (front + 1) % ARRAY_SIZE;
}
QUEUE_TYPE first()
{
assert(!is_empty());
return queue[front];
}
int is_empty()
{
return (rear + 1) % ARRAY_SIZE == front;
}
int is_full(void)
{
return (rear + 2) % ARRAY_SIZE == front;
}
*/
/*
** 引入一个全局变量
*/
static QUEUE_TYPE queue[QUEUE_SIZE];
static size_t cur_size = 0;
static front = 0;
static rear = 0;
void insert(QUEUE_TYPE value)
{
assert(!is_full());
rear = (rear+1) % QUEUE_SIZE;
queue[rear] = value;
cur_size++;
}
void delete()
{
assert(!is_empty());
front = (front+1) % QUEUE_SIZE;
cur_size--;
}
QUEUE_TYPE first()
{
assert(!is_empty());
return queue[front];
}
int is_empty()
{
return cur_size == 0;
}
int is_full()
{
return cur_size == QUEUE_SIZE;
}
test.c:
#include "queen.h"
#include <stdio.h>
void main()
{
insert('a');
delete();
insert('a');
delete();
insert('a');
delete();
insert('a');
delete();
insert('a');
delete();
//insert('a');
//insert('a');
//insert('a');
//insert('a');
//insert('a');
//delete();
//printf("first() = %c/n", first());
printf("is_empty: %d/n", is_empty());
printf("is_full: %d/n", is_full());
}