用C++ 实现顺序队列、链式队列的建立、进队、出队、返回队头元素、输出算法。

顺序队列代码实现：

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

#define MAXSIZE 100

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

void initQueue(SeqQueue *q) {
    q->front = q->rear = 0;
}

int isQueueEmpty(SeqQueue *q) {
    return q->front == q->rear;
}

int isQueueFull(SeqQueue *q) {
    return (q->rear + 1) % MAXSIZE == q->front;
}

int enQueue(SeqQueue *q, int x) {
    if (isQueueFull(q)) {
        printf("Queue is full!\n");
        return 0;
    }
    q->data[q->rear] = x;
    q->rear = (q->rear + 1) % MAXSIZE;
    return 1;
}

int deQueue(SeqQueue *q, int *x) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return 0;
    }
    *x = q->data[q->front];
    q->front = (q->front + 1) % MAXSIZE;
    return 1;
}

int getHead(SeqQueue *q, int *x) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return 0;
    }
    *x = q->data[q->front];
    return 1;
}

void printQueue(SeqQueue *q) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return;
    }
    printf("Queue: ");
    int i = q->front;
    while (i != q->rear) {
        printf("%d ", q->data[i]);
        i = (i + 1) % MAXSIZE;
    }
    printf("\n");
}

int main() {
    SeqQueue q;
    initQueue(&q);
    enQueue(&q, 1);
    enQueue(&q, 2);
    enQueue(&q, 3);
    printQueue(&q);
    int x;
    deQueue(&q, &x);
    printf("Dequeue: %d\n", x);
    printQueue(&q);
    getHead(&q, &x);
    printf("Queue head: %d\n", x);
    return 0;
}

链式队列代码实现：

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

typedef struct Node {
    int data;
    struct Node *next;
} Node, *QueuePtr;

typedef struct {
    QueuePtr front, rear;
} LinkQueue;

void initQueue(LinkQueue *q) {
    q->front = q->rear = (QueuePtr) malloc(sizeof(Node));
    if (!q->front) {
        printf("Memory allocation failed!\n");
        exit(1);
    }
    q->front->next = NULL;
}

int isQueueEmpty(LinkQueue *q) {
    return q->front == q->rear;
}

void enQueue(LinkQueue *q, int x) {
    QueuePtr p = (QueuePtr) malloc(sizeof(Node));
    if (!p) {
        printf("Memory allocation failed!\n");
        exit(1);
    }
    p->data = x;
    p->next = NULL;
    q->rear->next = p;
    q->rear = p;
}

int deQueue(LinkQueue *q, int *x) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return 0;
    }
    QueuePtr p = q->front->next;
    *x = p->data;
    q->front->next = p->next;
    if (q->rear == p) {
        q->rear = q->front;
    }
    free(p);
    return 1;
}

int getHead(LinkQueue *q, int *x) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return 0;
    }
    *x = q->front->next->data;
    return 1;
}

void printQueue(LinkQueue *q) {
    if (isQueueEmpty(q)) {
        printf("Queue is empty!\n");
        return;
    }
    printf("Queue: ");
    QueuePtr p = q->front->next;
    while (p != NULL) {
        printf("%d ", p->data);
        p = p->next;
    }
    printf("\n");
}

int main() {
    LinkQueue q;
    initQueue(&q);
    enQueue(&q, 1);
    enQueue(&q, 2);
    enQueue(&q, 3);
    printQueue(&q);
    int x;
    deQueue(&q, &x);
    printf("Dequeue: %d\n", x);
    printQueue(&q);
    getHead(&q, &x);
    printf("Queue head: %d\n", x);
    return 0;
}