链队列基本操作模拟系统

刺骨的言语ヽ痛彻心扉 2022-10-05 14:53 143阅读 0赞

#include<stdio.h>
    #include<stdlib.h>
    #define OK 1
    #define ERROR 0
    typedef short ElemType;
    typedef short Status;
    struct QNode/* 链队列的结点 */
    {
        ElemType data;
        struct QNode *next;
    };
    struct QueueInfo/* 链队列的头尾指针 */
    {
        QNode *Qfront;/* 队头指针 */
        QNode *Qrear; /* 队尾指针 */
    };
    /* */
    Status InitQueue(QueueInfo* &q);
    Status EnQueue(QueueInfo* &q, ElemType e);
    Status DeQueue(QueueInfo* &q, ElemType &e);
    ElemType GetHead(struct QueueInfo* &q);
    Status MenuPrint();
    Status QueueLength(struct QueueInfo* &q);
    Status Operation(struct QueueInfo* &q);
    /* */
    int main()
    {
        QueueInfo Q;
        QueueInfo *W = &Q;
        InitQueue(W);/* 初始化队列头结点 */
        MenuPrint();
        Operation(W);
    }
    /* 顶层操作函数 */
    Status Operation(struct QueueInfo* &q)
    {
        short choice;
        ElemType e;
        printf("Please input your choice from 1 to 5: ");
        while(scanf("%hd", &choice) != 1)
        {
            while(getchar() != '\n') ;
            printf("Now the input buffer has been cleaned, please input a valid number not a character.\n");
            printf("Please input your choice from 1 to 5: ");
        }
        while(1)
        {
            if(choice == 5)
            {
                printf("Thanks for your using, see you.\n");
                break;
            }
            switch(choice)
            {
                case 1:
                    printf("Please input the value of the element that will enter the queue: ");
                    scanf("%hd", &e);
                    if(EnQueue(q, e) == ERROR)
                    {
                        printf("The queue has already been full, so the element can not enter into it.\n");
                    }
                    break;
                case 2:
                    if(DeQueue(q, e) == OK)
                    {
                        printf("The element that have just been deleted from the queue is %hd.\n", e);
                    }
                    else
                    {
                        printf("The queue is now empty, so there is no element that can be deleted from it.\n");
                    }
                    break;
                case 3:
                    printf("The length of the queue is %hd now.\n", QueueLength(q));
                    break;
                case 4:
                    e = GetHead(q);
                    if(e != ERROR)
                    {
                        printf("The front element of the queue is %hd.\n", e);
                    }
                    else
                    {
                        printf("The queue is empty now, so there is no element in it.\n");
                    }
                    break;
                default:
                    printf("Please input a valid number from 1 to 5.\n");
                    break;
            }
            printf("Please input your choice from 1 to 5: ");
            while(scanf("%hd", &choice) != 1)
            {
                while(getchar() != '\n') ;
                printf("Now the input buffer has been cleaned, please input a valid number not a character.\n");
                printf("Please input your choice from 1 to 5: ");
            }
        }
        return OK;
    }
    /* 打印操作菜单 */
    Status MenuPrint()
    {
        printf("--------------------------顺序队列基本操作模拟系统--------------------------\n");
        printf("--------------------------1. 入队-------------------------------------------\n");
        printf("--------------------------2. 出队-------------------------------------------\n");
        printf("--------------------------3. 求队列长度-------------------------------------\n");
        printf("--------------------------4. 取队列的队头元素-------------------------------\n");
        printf("--------------------------5. 退出系统---------------------------------------\n");
        return OK;
    }
    /* 求队列长度 */
    Status QueueLength(struct QueueInfo* &q)
    {
        short len = 0;
        struct QNode *p = q -> Qfront -> next;
        while(p != NULL)
        {
            len ++;
            p = p -> next;
        }
        return len;
    }
    /* 取队头元素 */
    ElemType GetHead(struct QueueInfo* &q)
    {
        if(q -> Qfront == q -> Qrear)
        {
            /* 队空 */
            return ERROR;
        }
        return q -> Qfront -> next -> data;
    }
    /* 出队 */
    Status DeQueue(QueueInfo* &q, ElemType &e)
    {
        struct QNode *p;
        if(q -> Qfront == q -> Qrear)
        {
            /* 队空 */
            return ERROR;
        }
        p = q -> Qfront -> next;/* p指向队头元素 */
        e = p -> data;/* e保存队头元素的值 */
        q -> Qfront -> next = p -> next;/* 修改头结点的指针域 */
        if(p == q -> Qrear)
        {
            /* 最后一个元素被删除, 队尾指针指向头结点 */
            q -> Qrear = q -> Qfront;
        }
        free(p);
        return OK;
    }
    /* 入队 */
    Status EnQueue(QueueInfo* &q, ElemType e)
    {
        struct QNode *p = (struct QNode*)malloc(sizeof(struct QNode));
        if(p == NULL)
        {
            /* 申请动态内存失败 */
            exit(0);
        }
        p -> data = e;/* 将新结点数据域置为e */
        p -> next = NULL;
        q -> Qrear -> next = p;/* 将新结点插入到队尾 */
        q -> Qrear = p;
        return OK;
    }
    /* 初始化链队列 */
    Status InitQueue(QueueInfo* &q)
    {
        /* 链队的初始化操作就是构造一个只有一个头结点的空队 */
        /* 生成新结点作为头结点, 一开始队头和队尾指针都指向此结点 */
        q -> Qfront = (struct QNode*)malloc(sizeof(struct QNode));
        if(q -> Qfront == NULL)
        {
            /* 申请动态内存失败 */
            exit(0);
        }
        q -> Qrear = q -> Qfront;
        q -> Qfront -> next = NULL;
        return OK;
    }