循环队列的基本操作

头文件：SqQueue.h

#include<cstdlib>

#include<iostream>

using namespace std;

#define MAXQSIZE 100

#define TRUE 1

#define FALSE 0

#define OK 1

#define ERROR 0

#define INFEASIBLE -1

typedef int QElemType;

typedef int Status;

typedef struct

{

QElemType *base;

int front;

int rear;

}SqQueue;

//构造一个空队列

Status InitQueue(SqQueue& Q)

{

Q.base = (QElemType*)malloc(MAXQSIZE*sizeof(QElemType));

if (!Q.base)

exit(OVERFLOW);

Q.front = Q.rear = 0;

return OK;

}

//销毁队列Q

Status DestroyQueue(SqQueue& Q)

{

if (Q.base)

{

free(Q.base);

Q.base = NULL;

Q.front = Q.rear = 0;

}

return OK;

}

//清空队列Q

Status ClearQueue(SqQueue& Q)

{

Q.front = Q.rear = 0;

return OK;

}

//若队列Q为空，则返回TRUE;否则返回FALSE

Status QueueEmpty(SqQueue Q)

{

if (Q.front == Q.rear)

return TRUE;

else

return FALSE;

}

//返回Q的元素个数

int QueueLength(SqQueue Q)

{

return (Q.rear - Q.front + MAXQSIZE) % MAXQSIZE;

}

//若队列不空，则用e返回队列Q的队头元素，并返回OK;否则返回ERROR

Status GetHead(SqQueue Q, QElemType& e)

{

if (!QueueEmpty(Q))

{

e = Q.base[Q.front];

return OK;

}

return ERROR;

}

//插入元素e为Q新的队尾元素

Status EnQueue(SqQueue& Q, QElemType e)

{

if ((Q.rear + 1) % MAXQSIZE == Q.front)

return ERROR;

Q.base[Q.rear] = e;

Q.rear = (Q.rear + 1) % MAXQSIZE;

return OK;

}

//若队列不空，则删除Q的队头元素，用e返回其值，并返回OK;否则返回ERROR

Status DeQueue(SqQueue& Q, QElemType& e)

{

if (Q.front == Q.rear)

return ERROR;

e = Q.base[Q.front];

Q.front = (Q.front + 1) % MAXQSIZE;

return OK;

}

//打印输出队列的元素

Status visit(QElemType data)

{

if (cout << data << " ")

return OK;

else

return ERROR;

}

//依次对队列Q的元素调用函数visit().一旦调用visit()失败，则操作失败

Status QueueTraverse(SqQueue Q, Status(*visit)(QElemType))

{

int k = Q.front;

for (int i = 1; i <= QueueLength(Q); ++i)

{

if (!(*visit)(Q.base[k]))

return ERROR;

k = (k + 1) % MAXQSIZE;

}

cout << endl;

return OK;

}

主程序：
#include"SqQueue.h"

void main(void)

{

SqQueue Q;

InitQueue(Q);

for (int i = 1; i < 20; i += 2)

EnQueue(Q, i);

cout << "队列Q的基本信息：" << endl;

QueueTraverse(Q, visit);

cout << "Q的长度为:" << QueueLength(Q) << endl;

cout << "Q的队头元素为:";

QElemType e;

GetHead(Q, e);

cout << e << endl;

cout << "Q是否为空：";

if (!QueueEmpty(Q))

{

cout << "否！" << endl;

int i = 1;

while (i <= QueueLength(Q))

{

DeQueue(Q, e);

++i;

}

}

else

cout << "是！";

DestroyQueue(Q);

}