链式队列实现

三个文件：main.c student.c student.h

student.h文件如下：

#ifndef STUDENT_H_
#define STUDENT_H_

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

#define CMD_ADD_NODE  ‘1‘
#define CMD_DEL_NODE  ‘2‘
#define CMD_SHOW_NODE ‘3‘
#define CMD_QUIT_NODE  ‘4‘ 

#define MAX 10

typedef struct
{
    char name[20];
    int grade;
}Item;
typedef struct node
{
    Item item;
    struct node *next;
}Node;
typedef struct
{
    Node *front; /* 队头指针 */
    Node *rear;  /* 队尾指针 */
    int items;
}Queue;

static inline void print(const Item item)
{
    printf("%s, %d\n", item.name, item.grade);
    return ;
}

int QueueAdd( Queue *queue,Item item);
int QueueDel(Queue *queue, Item *item);
int QueueShow(const Queue *queue);

#endif

main.c文件如下：

#include"student.h"

int main(int argc, char **argv)
{
    char cmd = 0;
    Queue queue={NULL,NULL,0};
    Item item;

    //Initialize(&queue);
    while(1)
    {
        printf("The Menun Is:\n");
        printf("1.add\n");
        printf("2.delete\n");
        printf("3.show\n");
        printf("4.quit\n");
        printf("Enter your choice(1~4):");

        cmd = getchar();
        while( (getchar()) != ‘\n‘ )
            continue;//跳过输入行的多余部分
        while( cmd != CMD_ADD_NODE && cmd != CMD_DEL_NODE
                           && cmd != CMD_SHOW_NODE && cmd != CMD_QUIT_NODE)
        {
            printf("Please input 1~4:");
            cmd = getchar();
            while( (getchar()) != ‘\n‘ )
                    continue;//跳过输入行的多余部分
        }

        switch(cmd)
        {
            case CMD_ADD_NODE  :
                printf("Enter name and grade:");
                scanf("%s%d",item.name,&(item.grade));
                while( (getchar()) != ‘\n‘ )
                    continue;//跳过输入行的多余部分
                QueueAdd(&queue, item);
                break;

            case CMD_DEL_NODE  :
                QueueDel(&queue, &item);
                printf("Delete:");
                print(item);
                break;

            case CMD_SHOW_NODE  :
                QueueShow(&queue);
                break;

            case CMD_QUIT_NODE  :
                exit(0);
                break;

            default:
                break;
        }
        printf("\n");
    }
    return 0;
}

student.c文件如下：

#include "student.h"

static int  QueueIsEmpty(const  Queue *queue)
{
        return (queue->items == 0);
}

static int QueueIsFull(const Queue *queue)
{
        return (queue->items == MAX);
}

/* 插到队尾 */
int QueueAdd(Queue *queue, Item item)
{
    Node *node;

    if( QueueIsFull(queue) )
    {
            fprintf(stderr,"The queue is full!!!\n");
            return -1;
    }

    node = (Node *)malloc(sizeof(Node));
    if(node == NULL)
    {
        fprintf(stderr, "Cannot creat a node!!!\n");
        return -1;
    }
    node->item = item;
    node->next = NULL;

    if( QueueIsEmpty(queue) )
    {
            queue->front = node;
    }
    else
    {
            queue->rear->next = node;
    }
    queue->rear = node;
    queue->items ++;

    return 0;
}

/* 在队头删除 */
int QueueDel( Queue *queue,  Item *item )
{
        Node *node;

        if( QueueIsEmpty(queue) )
        {
                fprintf(stderr, "The queue is empty!!!\n");
                return -1;
        }

        *item = queue->front->item;
        node = queue->front;
        queue->front = node->next;
        queue->items --;

        free(node);

        return 0;
}

int  QueueShow( const Queue *queue )
{
        int i;
        Node *node = queue->front;

        if( QueueIsEmpty(queue) )
        {
                fprintf(stderr, "The queue is empty!!!\n");
                return -1;
        }

        printf("All of the student:\n");
        for( i=0; i<(queue->items); i++ )
        {
                print(node->item);
                node = node->next;
        }
        printf("\n");

        return 0;
}