【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