【数据结构】数据结构C语言的实现（队列）

队列

/*
* 链式队列
*/
#include <stdio.h>
#include <stdlib.h>

#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define OVERFLOW -2

typedef int QElemType;
typedef int Status;

typedef struct QNode
{
QElemType data;     // 元素数据
struct QNode *next; // 指向下一个元素的指针
} QNode, *QueuePtr;

typedef struct
{
QueuePtr front;     // 队首指针  Q->front->next指向第一个元素
QueuePtr rear;      // 队尾指针  Q->rear指向最后一个元素
} LinkQueue;

// 初始化队列
Status InitQueue(LinkQueue *Q)
{
Q->front = Q->rear = (QueuePtr)malloc(sizeof(QNode));
if (!Q->front)
exit(OVERFLOW);
Q->front->next = NULL;
return OK;
}

// 销毁队列
Status DestroyQueue(LinkQueue *Q)
{
while (Q->front)
{
Q->rear = Q->front->next;
free(Q->front);
Q->front = Q->rear;
}
return OK;
}

// 清空队列
Status ClearQueue(LinkQueue *Q)
{
DestroyQueue(Q);
InitQueue(Q);
return OK;
}

// 判断队列是否为空
Status IsEmpty(LinkQueue Q)
{
if (Q.front->next == NULL)
return TRUE;
else
return FALSE;
}

// 获取队列长度
int GetLength(LinkQueue Q)
{
int i = 0;
QueuePtr p = Q.front;
while (Q.rear != p)
{
i++;
p = p->next;
}
return i;
}

Status GetHead(LinkQueue Q, QElemType *e)
{
QueuePtr p;
if (Q.front == Q.rear)
return ERROR;

p = Q.front->next;
*e = p->data;
return OK;
}

// 入队
Status EnQueue(LinkQueue *Q, QElemType e)
{
QueuePtr p = (QueuePtr)malloc(sizeof(QNode));
if (!p)
exit(ERROR);

p->data = e;
p->next = NULL;
Q->rear->next = p;
Q->rear = p;
return OK;
}

// 出队
Status DeQueue(LinkQueue *Q, QElemType *e)
{
QueuePtr p;
if (Q->front == Q->rear)
return ERROR;

p = Q->front->next;
*e = p->data;
Q->front->next = p->next;
if (Q->rear == p)
Q->rear = Q->front;
free(p);
return OK;
}

// 访问元素
void visit(QElemType e)
{
printf("%d ", e);
}

// 遍历队列
Status TraverseQueue(LinkQueue Q, void (*visit)(QElemType))
{
QueuePtr p = Q.front->next;
while (p)
{
visit(p->data);
p = p->next;
}
printf("\n");
return OK;
}

int main()
{
LinkQueue Q;
if (InitQueue(&Q))
{
QElemType e;
int i;

printf("init_success\n");

if (IsEmpty(Q))
printf("queue is empty\n");
for (i = 0; i < 10; i++)
EnQueue(&Q, i);

GetHead(Q, &e);
printf("The first element is %d\n", e);
printf("length is %d\n", GetLength(Q));
DeQueue(&Q, &e);
printf("delete element is %d\n", e);
TraverseQueue(Q, *visit);
EnQueue(&Q, 10);
printf("Insert element is %d\n", 10);
TraverseQueue(Q, *visit);

if (DestroyQueue(&Q))
printf("\ndestroy_success\n");
}
}

init_success
queue is empty
The first element is 0
length is 10
delete element is 0
1 2 3 4 5 6 7 8 9
Insert element is 10
1 2 3 4 5 6 7 8 9 10

destroy_success