（数据结构）利用 C语言实现顺序队列及链队列定义一个包含学生信息（学号，姓名，成绩）的顺序队列和链队列，使其具有如下功能： (1) 初始化一个空队列； (2) 逐个输入学生信息并入队； (3) 出队，输出学号、姓名、成绩等信息； (4) 删除队列。 (5) 统计当前队列排队学生个数；

顺序队列的实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXSIZE 100

typedef struct {
    char id[20];
    char name[20];
    int score;
} Student;

typedef struct {
    Student data[MAXSIZE];
    int front, rear;
} SeqQueue;

void InitQueue(SeqQueue *Q)
{
    Q->front = Q->rear = 0;
}

int QueueLength(SeqQueue Q)
{
    return (Q.rear - Q.front + MAXSIZE) % MAXSIZE;
}

int Enqueue(SeqQueue *Q, Student stu)
{
    if ((Q->rear + 1) % MAXSIZE == Q->front) {
        // 队列已满
        return 0;
    }
    Q->data[Q->rear] = stu;
    Q->rear = (Q->rear + 1) % MAXSIZE;
    return 1;
}

int Dequeue(SeqQueue *Q, Student *stu)
{
    if (Q->front == Q->rear) {
        // 队列为空
        return 0;
    }
    *stu = Q->data[Q->front];
    Q->front = (Q->front + 1) % MAXSIZE;
    return 1;
}

void DestroyQueue(SeqQueue *Q)
{
    Q->front = Q->rear = 0;
}

int main()
{
    int n = 0, i = 0;
    SeqQueue Q;
    Student stu;

    InitQueue(&Q);

    printf("请输入学生人数：");
    scanf("%d", &n);

    printf("请逐个输入学生信息（学号、姓名、成绩）：\n");
    for (i = 0; i < n; i++) {
        printf("第 %d 个学生：", i + 1);
        scanf("%s %s %d", stu.id, stu.name, &stu.score);
        if (!Enqueue(&Q, stu)) {
            printf("队列已满，无法插入！\n");
            break;
        }
    }

    printf("\n当前队列中有 %d 个学生：\n", QueueLength(Q));
    while (Dequeue(&Q, &stu)) {
        printf("学号：%s，姓名：%s，成绩：%d\n", stu.id, stu.name, stu.score);
    }

    DestroyQueue(&Q);

    return 0;
}

链队列的实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct Node {
    char id[20];
    char name[20];
    int score;
    struct Node *next;
} Student;

typedef struct {
    Student *front, *rear;
} LinkQueue;

void InitQueue(LinkQueue *Q)
{
    Q->front = Q->rear = (Student*)malloc(sizeof(Student));
    if (!Q->front) {
        printf("内存分配失败！\n");
        exit(1);
    }
    Q->front->next = NULL;
}

int QueueLength(LinkQueue Q)
{
    Student *p = Q.front->next;
    int len = 0;
    while (p) {
        len++;
        p = p->next;
    }
    return len;
}

int Enqueue(LinkQueue *Q, Student stu)
{
    Student *newNode;
    newNode = (Student*)malloc(sizeof(Student));
    if (!newNode) {
        printf("内存分配失败！\n");
        exit(1);
    }
    newNode->score = stu.score;
    strcpy(newNode->id, stu.id);
    strcpy(newNode->name, stu.name);
    newNode->next = NULL;
    Q->rear->next = newNode;
    Q->rear = newNode;
    return 1;
}

int Dequeue(LinkQueue *Q, Student *stu)
{
    Student *p;
    if (Q->front == Q->rear) {
        // 队列为空
        return 0;
    }
    p = Q->front->next;
    Q->front->next = p->next;
    if (Q->rear == p) {
        // 若被删的是队尾结点，则修改队尾指针
        Q->rear = Q->front;
    }
    *stu = *p;
    free(p);
    return 1;
}

void DestroyQueue(LinkQueue *Q)
{
    Student *p = Q->front, *q;
    while (p) {
        q = p->next;
        free(p);
        p = q;
    }
    Q->front = Q->rear = NULL;
}

int main()
{
    int n = 0, i = 0;
    LinkQueue Q;
    Student stu;

    InitQueue(&Q);

    printf("请输入学生人数：");
    scanf("%d", &n);

    printf("请逐个输入学生信息（学号、姓名、成绩）：\n");
    for (i = 0; i < n; i++) {
        printf("第 %d 个学生：", i + 1);
        scanf("%s %s %d", stu.id, stu.name, &stu.score);
        if (!Enqueue(&Q, stu)) {
            printf("内存分配失败，无法插入！\n");
            break;
        }
    }

    printf("\n当前队列中有 %d 个学生：\n", QueueLength(Q));
    while (Dequeue(&Q, &stu)) {
        printf("学号：%s，姓名：%s，成绩：%d\n", stu.id, stu.name, stu.score);
    }

    DestroyQueue(&Q);

    return 0;
}