队列的c语言实现

队列是一种与栈相反的数据结构，它是先进先出（first in, first out),同样它也是一种运算受限的结构。

队列的抽象数据类型：

ADT QUEUE =

{

InitQueue(&Q)

//create a queue

DestroyQueue(&q)

//destroy a queue

clearQueue(&q)

//clear the queue

............

}

队列的c语言实现

1：

顺序队列：

/* ******************************************
* FileName:squeue.c
* Author:hufeng Date:2007/11/21
* Version:v1.0
* Description: The program creat a queue and lots
* of operating
* ******************************************/

/* header file */
#include <stdio.h>
#define MAX 20

/* creat a struct */
typedef struct squeue
{
int date[MAX]; /*declartion a array */
int front,rear; /* declarion a front and a rear pointer */

}sq;

/* assign queue each elem */
void Assign_squeue(sq *p, int count)
{
int i; /* declaration a cycle variable */

    if (p->rear > MAX - 1)
        {
            printf("Overflow!\n");
            return;
        }

    printf("Please enter each elem:\n");
    for (i = 0; i < count; i++)
        {
            scanf("%d", &p->date[++p->rear]);
        }
}

/* insert a new elem in the queue */
void Insert_squeue(sq *p, int num)
{
    if (p->rear > MAX - 1)
        {
            printf("Over flow!\n");
            return;
        }

    else
        {
            p->date[++p->rear] = num;
        }

}

/* Delete a elem */
void Delete_squeue(sq *p)
{
    int x;
    if (p->front == p->rear)
        {
            printf("Empty queue!\n");
            return;
        }
    else
        {
            x = p->date[++p->front];
            printf("P->front = %d\n",p->front);
            printf("The deleted number is:%d\n",x);
        }
}

/* main program */
int main()
{
sq *p = NULL; /* declaration a pointer */
int num; /* decalration a number of queue */

p->front = -1;
p->rear = p->front;

printf("Please enter the length of queue:\n");
scanf("%d", &num);

Assign_squeue(p, num); /* assign array date */

    /* insert a number in the queue */
    printf("Please enter which number you want to insert:\n");
    scanf("%d", &num);
    Insert_squeue(p, num);

/* delete a number */
Delete_squeue(p);

getch();
return 0;

}

2：

循环队列：

/* ******************************************
* FileName:cycle_queue.c
* Author:hufeng Date:2007/11/21
* Version:v1.0
* Description:The program is a cycle queue
*********************************************/

/* header file */
#include <stdio.h>
#define MAX 20

/* creat a struct */
typedef struct cycle_queue
{
int date[MAX];
int front,rear;
}cq;

/* assign queue */
void Assign_CycleQueue(cq *p, int n)
{
int i;
int x;

    if (n < 1 || n > MAX - 1)
        {
            printf("Overflow!\n");
            return;
        }

   printf("Please enter each elem:\n");
   for (i = 0; i < n; i++)
        {
            scanf("%d", &x);
            p->date[p->rear++] = x;
        }
}

/* insert a number */
void Insert_CycleQueue(cq *p, int num)
{
    if ((p->rear + 1) % MAX == p->front)
        {
            printf("full queue!\n");
            return;
        }
    else
        {
            p->date[++p->rear] = num;
        }
}

/* delete number */
void Delete_CycleQueue(cq *p)
{
    int x;
    if ((p->front + 1) % MAX == p->rear)
        {
            printf("empty queue!\n");
            return;
        }

   x = p->date[p->front];
   printf("p->front = %d\n", p->front);
   printf("The deleted number is:%d\n",x);
}

/* main program */
int main()
{

    int num;
    cq *p = NULL;
    p->front = 0;
    p->rear = p->front;

printf("Please enter the length of queue:\n");
scanf("%d", &num);

Assign_CycleQueue(p,num);

printf("Please enter the inserting number:\n");
scanf("%d",&num);

Insert_CycleQueue(p, num);
Delete_CycleQueue(p);

getch();
return 0;
}

3.

链队：