链队列

#define _CRT_SECURE_NO_WARNINGS//不加此行，vs下会报scanf()函数错
#define DataType int

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

typedef struct node
{
    DataType data;
    struct node* next;
}QNode;

typedef struct
{
    QNode* front;
    QNode* rear;
}LQueue;

int main(void)
{
    int x;//入队元素
    int number;//出队个数
    LQueue* q = (LQueue*)calloc(1, sizeof(LQueue));//初始化
    QNode* p = (QNode*)calloc(1,sizeof(QNode));
    p->next = NULL;
    q->front = p;
    q->rear = p;


    printf("请输入入队的元素:");//入队
    scanf("%d", &x);
    while (x != -1)
    {
        if ((p = (QNode*)calloc(1, sizeof(QNode))) == NULL)
        {
            printf("\nclear and allocation fail!");
            return -1;
        }
        p->next = q->rear->next;
        p->data = x;
        q->rear->next = p;
        q->rear = p;
        scanf("%d", &x);
    }

    printf("\n请输入出队个数：");
    scanf("%d", &number);
    while (number != 0)
    {
        if (q->front == q->rear)
        {
            printf("\n队空!");
            return -1;
        }
        p = q->front->next;
        q->front->next = p->next;
        free(p);
        if (q->front->next == NULL)//只有一个元素时，出队后队空，修改队尾指针
        {
            q->rear = q->front;
        }
        number--;
    }

    if (q->front == q->rear)//打印
    {
        printf("\n空队!");
        return -1;
    }
    printf("\nfront");
    p = q->front;
    do
    {
        p = p->next;
        printf("->%d", p->data);
    } while (p != q->rear);

    system("pause");
    return 0;
}