（1）编写实现队列的五个基本运算；
（2）队列中能容纳元素的最多个数还是 m0-1 吗?
队列为空:count==0,front==0;
队列为满:count==m0;
My View;有三个关键的地方:1,模运算的作用:数字在一定范围循环,实现首尾相连;
2,数组的序号变化:控制在0-(m0-1)范围内;
3,count:控制在1-m0范围内.
CODE:
#include <stdio.h>#include <stdlib.h>#define m0 5//最大队列长度typedef int QElemType;//队列元素类型
typedef struct{
typedef 
QElemType *base;//初始化的动态分配存储空间 int front; int count;
}SqQueue;//构造空队列SqQueue* makeQueue(){ SqQueue *Q = (SqQueue *) malloc(sizeof(SqQueue)); if(!Q)printf("OVERFLOW! ");
Q -> base = (QElemType *) malloc (m0 * sizeof (QElemType));/*比较关键的一步*/
Q if(!Q -> base)printf("OVERFLOW! "); Q -> front = 0; Q -> count = 0; return Q;}//判断队列是否为空int isEmpty(SqQueue *Q){ if(Q -> count == 0) return 1; else return 0;}//判断队列是否已满int isFull(SqQueue *Q){ if(Q -> count == m0) return 1; else return 0;}//取队头元素QElemType pop(SqQueue *Q){ QElemType h = 0; if(isEmpty(Q)) printf("Sorry,the queue is empty! ");//队列下溢出 h = Q -> base[Q -> front]; return h;}//将元素e入列void enQueue(SqQueue *Q,QElemType e){ if(isFull(Q)){ printf("Queue overFlow! ");//队列上溢出
} int place; place = (Q -> front + Q -> count) % m0; Q -> base[place] = e; Q -> count = (Q -> count + 1) % (m0 + 1); if(Q -> count == 0) Q -> count = 1;//确保count在1-5循环}//删除头元素void deQueue(SqQueue *Q){ if(isEmpty(Q)) printf("Queue underFlow! ");//队列下溢出 else{ Q -> front =(Q -> front + 1) % m0; Q -> count --; }}//打印当前队列void print(SqQueue *Q){ if(isEmpty(Q)) printf("Sorry,the queue is empty! ");//队列下溢出 else{ int p = Q -> count; int i = 0; printf("Now,there are %d elements of queue :",p); while(p!=0){ int place = (Q -> front + i) % m0; printf("%d,",Q -> base[place]); i++; p--; } printf(" "); }}
测试代码:
#include <stdio.h>#include "sqqueue.h"typedef int ElemType;void main(){ ElemType h; SqQueue *queue = makeQueue(); print(queue); deQueue(queue); enQueue(queue,1); enQueue(queue,2); enQueue(queue,3); enQueue(queue,4); print(queue); deQueue(queue); deQueue(queue); deQueue(queue); enQueue(queue,5); print(queue); enQueue(queue,6); print(queue); deQueue(queue); enQueue(queue,7); print(queue);}
RUN:
Q2:假定用一个循环单链表表示队列（称为循环队列），该队列只设一个队尾指针 rear，不设队首指针，编写如下函数：
（1）向循环链队中插入一个元素为 x 的结点；
（2）从循环链队中删除一个结点。
My View:在构造队列时,有一个关键的地方:以节点为中心.
CODE:
#include <stdio.h>#include <stdlib.h>typedef struct QNode{ int data; struct QNode *next;}QNode, *QueuePtr;//节点定义符typedef struct{ QueuePtr rear;//队尾指针}LinkQueue;//队列定义符号/*构造队列*/LinkQueue* makeQueue(){ LinkQueue *Q = (LinkQueue *) malloc(sizeof(LinkQueue)); if(!Q)printf("Q:OVERFLOW ");//存储分配失败 else{ Q->rear=NULL; //Q->rear->next = Q->rear; } return Q;}//构造节点QueuePtr makeNode(int i){ QueuePtr N = (QueuePtr)malloc(sizeof(QNode)); if(!N)printf("Node:OVERFLOW ");//存储分配失败 else{ N->data=i; N->next=NULL; } return N;}//判断队列是否为空int isEmpty(LinkQueue *Q){ if(Q->rear == NULL) return 1; else return 0;}//将队列置空void makeNull(LinkQueue *Q){ if(!isEmpty(Q)) printf("错误：队列为空！"); else{ Q->rear->next = NULL; }}//删除队列第一个元素void deQueue(LinkQueue *Q){ if(isEmpty(Q)) printf("错误：队列为空！ "); else{ QueuePtr p; p = Q->rear->next; Q->rear->next = p->next; free(p); }}/*返回队列的第一个元素*/int front(LinkQueue *Q){ int x; if(!isEmpty(Q)) x=(Q->rear->next->data); return x;}/*把元素x插入到队列右端*/void enqueue(LinkQueue *Q,int e){ QueuePtr p = makeNode(e); if(isEmpty(Q)){//如果队列为空 Q->rear = p; Q->rear->next = p;//这个很关键,要以节点为中心 /*Q->rear = Q->rear->next;这是错误的表达*/ } else{//如果队列不为空 p->next = Q->rear->next; Q->rear->next = p; Q->rear = p; }}/*打印链表*/void print(LinkQueue *Q){ if(!isEmpty(Q)){//判断队列是否为空 QueuePtr p = (QueuePtr)malloc(sizeof(QNode)); if(!p)printf("Node:OVERFLOW ");//存储分配失败 else{ printf("队列为:"); p=Q->rear->next; do { printf("%d",p->data); printf(","); if(p == Q->rear) break; p=p->next; }while(1); printf(" "); } } else printf("错误:检测到队列为空,无法打印! ");}
测试代码：
#include <stdio.h>#include "nofront.h"void main(){ LinkQueue *Queue = makeQueue(); print(Queue); enqueue(Queue,3); enqueue(Queue,4); enqueue(Queue,5); enqueue(Queue,6); print(Queue); int h = front(Queue); printf("the first element is %d ",h); deQueue(Queue); print(Queue); enqueue(Queue,7); print(Queue);}
RUN:
闪……