数据结构封装之《SeqQueue2.0改进顺序式队列》

说明：

1. 本队列是对SeqQueue的改进实现；有关SeqQueue1.0，请转到： 数据结构封装之 《SeqQueue顺序式队列》；

2. 本顺序式队列，在原有的基础上，增加了两个标志位front和rear，分别代表队列“头”和队列“尾”在顺序表中的下标。

3. 相比于上个版本的优点（其实也只有1个）： 规避了删除队列头时，产生队列元素移动的操作。其机制是通过front和rear作为头和尾的下标，队列的进出，实质上就是下标的移动，模拟了循环队列的方式，从而避免了对顺序表内元素的移动。

4. 相比于LinkQueue2.0，缺点是，队列限制了长度。

下面将给出该数据结构的代码，每个函数的结构分析 ，以及个别主要函数的汇编分析

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代码：

SeqQueue.h

#ifndef _SEQQUEUE_H_#define _SEQQUEUE_H_typedef void SeqQueue;SeqQueue* SeqQueue_Create(int capacity);void SeqQueue_Destroy(SeqQueue* queue);void SeqQueue_Clear(SeqQueue* queue);int SeqQueue_Append(SeqQueue* queue, void* item);void* SeqQueue_Retrieve(SeqQueue* queue);void* SeqQueue_Header(SeqQueue* queue);int SeqQueue_Length(SeqQueue* queue);int SeqQueue_Capacity(SeqQueue* queue);#endif

SeqQueue.c

#include <stdio.h>#include <malloc.h>#include "SeqQueue.h"typedef unsigned int TSeqQueueNode;typedef struct _tag_SeqQueue{    int capacity;    int length;    int front;    int rear;    TSeqQueueNode* node;} TSeqQueue;SeqQueue* SeqQueue_Create(int capacity) // O(1){    TSeqQueue* ret = NULL;    if( capacity >= 0 )    {        ret = (TSeqQueue*)malloc(sizeof(TSeqQueue) + sizeof(TSeqQueueNode) * capacity);    }    if( ret != NULL )    {        ret->capacity = capacity;        ret->length = 0;        ret->front = 0;        ret->rear = 0;        ret->node = (TSeqQueueNode*)(ret + 1);    }    return ret;}void SeqQueue_Destroy(SeqQueue* queue) // O(1){    free(queue);}void SeqQueue_Clear(SeqQueue* queue) // O(1){    TSeqQueue* sQueue = (TSeqQueue*)queue;    if( sQueue != NULL )    {        sQueue->length = 0;        sQueue->front = 0;        sQueue->rear = 0;    }}int SeqQueue_Append(SeqQueue* queue, void* item) // O(1){    TSeqQueue* sQueue = (TSeqQueue*)queue;    int ret = (sQueue != NULL) && (item != NULL);    ret = ret && (sQueue->length + 1 <= sQueue->capacity);    if( ret )    {        sQueue->node[sQueue->rear] = (TSeqQueueNode)item;        sQueue->rear = (sQueue->rear + 1) % sQueue->capacity;        sQueue->length++;    }    return ret;}void* SeqQueue_Retrieve(SeqQueue* queue) // O(1){    TSeqQueue* sQueue = (TSeqQueue*)queue;    void* ret = SeqQueue_Header(queue);    if( ret != NULL )    {        sQueue->front = (sQueue->front + 1) % sQueue->capacity;        sQueue->length--;    }    return ret;}void* SeqQueue_Header(SeqQueue* queue) // O(1) {    TSeqQueue* sQueue = (TSeqQueue*)queue;    void* ret = NULL;    if( (sQueue != NULL) && (sQueue->length > 0) )    {        ret = (void*)(sQueue->node[sQueue->front]);    }    return ret;}int SeqQueue_Length(SeqQueue* queue) // O(1){    TSeqQueue* sQueue = (TSeqQueue*)queue;    int ret = -1;    if( sQueue != NULL )    {        ret = sQueue->length;    }    return ret;}int SeqQueue_Capacity(SeqQueue* queue) // O(1){    TSeqQueue* sQueue = (TSeqQueue*)queue;    int ret = -1;    if( sQueue != NULL )    {        ret = sQueue->capacity;    }    return ret;}

main.c

#include <stdio.h>#include <stdlib.h>#include "SeqQueue.h"int main(int argc, char *argv[]) {    SeqQueue* queue = SeqQueue_Create(6);    int a[10] = {0};    int i = 0;    for(i=0; i<10; i++)    {        a[i] = i + 1;        SeqQueue_Append(queue, a + i);    }    printf("Header: %d\n", *(int*)SeqQueue_Header(queue));    printf("Length: %d\n", SeqQueue_Length(queue));    printf("Capacity: %d\n", SeqQueue_Capacity(queue));    while( SeqQueue_Length(queue) > 0 )    {        printf("Retrieve: %d\n", *(int*)SeqQueue_Retrieve(queue));    }    printf("\n");    for(i=0; i<10; i++)    {        a[i] = i + 1;        SeqQueue_Append(queue, a + i);        printf("Retrieve: %d\n", *(int*)SeqQueue_Retrieve(queue));    }    SeqQueue_Destroy(queue);    return 0;}

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函数结构分析：

1.SeqQueue_Create

2.SeqQueue_Destroy

3.SeqQueue_Clear

4.SeqQueue_Append

5.SeqQueue_Retrieve

6.SeqQueue_Header

7.SeqQueue_Length

8.SeqQueue_Capacity

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汇编分析：

main

1.SeqQueue_Create

2.SeqQueue_Destroy

4.SeqQueue_Append

5.SeqQueue_Retrieve

6.SeqQueue_Header

7.SeqQueue_Length

8.SeqQueue_Capacity