（1）編寫實現隊列的五個基本運算；
（2）隊列中能容納元素的最多個數還是 m0-1 嗎?
隊列爲空:count==0,front==0;
隊列爲滿:count==m0;
My View;有三個關鍵的地方:1,模運算的作用:數字在一定範圍循環,實現首尾相連;
2,數組的序號變化:控制在0-(m0-1)範圍內;
3,count:控制在1-m0範圍內.
CODE:
#include <stdio.h>#include <stdlib.h>#define m0 5//最大隊列長度typedef int QElemType;//隊列元素類型
typedef struct{
typedef 
QElemType *base;//初始化的動態分配存儲空間 int front; int count;
}SqQueue;//構造空隊列SqQueue* makeQueue(){ SqQueue *Q = (SqQueue *) malloc(sizeof(SqQueue)); if(!Q)printf("OVERFLOW! ");
Q -> base = (QElemType *) malloc (m0 * sizeof (QElemType));/*比較關鍵的一步*/
Q if(!Q -> base)printf("OVERFLOW! "); Q -> front = 0; Q -> count = 0; return Q;}//判斷隊列是否爲空int isEmpty(SqQueue *Q){ if(Q -> count == 0) return 1; else return 0;}//判斷隊列是否已滿int isFull(SqQueue *Q){ if(Q -> count == m0) return 1; else return 0;}//取隊頭元素QElemType pop(SqQueue *Q){ QElemType h = 0; if(isEmpty(Q)) printf("Sorry,the queue is empty! ");//隊列下溢出 h = Q -> base[Q -> front]; return h;}//將元素e入列void enQueue(SqQueue *Q,QElemType e){ if(isFull(Q)){ printf("Queue overFlow! ");//隊列上溢出
} 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;//確保count在1-5循環}//刪除頭元素void deQueue(SqQueue *Q){ if(isEmpty(Q)) printf("Queue underFlow! ");//隊列下溢出 else{ Q -> front =(Q -> front + 1) % m0; Q -> count --; }}//打印當前隊列void print(SqQueue *Q){ if(isEmpty(Q)) printf("Sorry,the queue is empty! ");//隊列下溢出 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(" "); }}
測試代碼:
#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:假定用一個循環單鏈表表示隊列（稱爲循環隊列），該隊列只設一個隊尾指針 rear，不設隊首指針，編寫如下函數：
（1）向循環鏈隊中插入一個元素爲 x 的結點；
（2）從循環鏈隊中刪除一個結點。
My View:在構造隊列時,有一個關鍵的地方:以節點爲中心.
CODE:
#include <stdio.h>#include <stdlib.h>typedef struct QNode{ int data; struct QNode *next;}QNode, *QueuePtr;//節點定義符typedef struct{ QueuePtr rear;//隊尾指針}LinkQueue;//隊列定義符號/*構造隊列*/LinkQueue* makeQueue(){ LinkQueue *Q = (LinkQueue *) malloc(sizeof(LinkQueue)); if(!Q)printf("Q:OVERFLOW ");//存儲分配失敗 else{ Q->rear=NULL; //Q->rear->next = Q->rear; } return Q;}//構造節點QueuePtr makeNode(int i){ QueuePtr N = (QueuePtr)malloc(sizeof(QNode)); if(!N)printf("Node:OVERFLOW ");//存儲分配失敗 else{ N->data=i; N->next=NULL; } return N;}//判斷隊列是否爲空int isEmpty(LinkQueue *Q){ if(Q->rear == NULL) return 1; else return 0;}//將隊列置空void makeNull(LinkQueue *Q){ if(!isEmpty(Q)) printf("錯誤：隊列爲空！"); else{ Q->rear->next = NULL; }}//刪除隊列第一個元素void deQueue(LinkQueue *Q){ if(isEmpty(Q)) printf("錯誤：隊列爲空！ "); else{ QueuePtr p; p = Q->rear->next; Q->rear->next = p->next; free(p); }}/*返回隊列的第一個元素*/int front(LinkQueue *Q){ int x; if(!isEmpty(Q)) x=(Q->rear->next->data); return x;}/*把元素x插入到隊列右端*/void enqueue(LinkQueue *Q,int e){ QueuePtr p = makeNode(e); if(isEmpty(Q)){//如果隊列爲空 Q->rear = p; Q->rear->next = p;//這個很關鍵,要以節點爲中心 /*Q->rear = Q->rear->next;這是錯誤的表達*/ } else{//如果隊列不爲空 p->next = Q->rear->next; Q->rear->next = p; Q->rear = p; }}/*打印鏈表*/void print(LinkQueue *Q){ if(!isEmpty(Q)){//判斷隊列是否爲空 QueuePtr p = (QueuePtr)malloc(sizeof(QNode)); if(!p)printf("Node:OVERFLOW ");//存儲分配失敗 else{ printf("隊列爲:"); p=Q->rear->next; do { printf("%d",p->data); printf(","); if(p == Q->rear) break; p=p->next; }while(1); printf(" "); } } else printf("錯誤:檢測到隊列爲空,無法打印! ");}
測試代碼：
#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:
閃……