风险程序，查不出错在哪

[reiliu]

#include<iostream>
using namespace std;
#define MaxLength 6
typedef int elemType;

class Queue
{
public:
Queue();
int QueueLength();
void EnQueue(elemType e);
int DeQueue(elemType &e);

protected:
elemType *Q;
elemType front;
elemType rear;
elemType counter;
elemType a[MaxLength];


};


Queue::Queue()
{

elemType *Q = new elemType( MaxLength );
if(!Q)
return ;
front = rear=0;
counter = 0;
}


int Queue::QueueLength()
{
return counter;
}


void Queue::EnQueue(elemType e)
{
if(counter == MaxLength)
return ;
Q[rear] = e;
rear = (rear + 1)%MaxLength;
counter++;

}


int Queue::DeQueue( elemType &e)
{
if(counter == 0)
return 1;
e= Q[front];
front = (front + 1)%MaxLength;
counter--;
return e;
}

int main()
{
Queue a;
int Length = 0;
Length = a.QueueLength();
cout<<Length;
a.EnQueue(12);
int LE = 0;
LE = a.QueueLength();
cout<<LE;
return 0;
}


这是我数据结构实验上的题目，用VC6.0编译错误指向Q[rear] = e 和 e= Q[front]，但是我实在不知道错在哪,请各位高手指点

[FreeKid]

elemType *Q = new elemType( MaxLength );

这里你想分配啥？是不是写错了？

[reiliu]

elemType *Q = new elemType( MaxLength );
这里我想创建一个长度为MaxLength的循环队列；

[peachswallow]

"elemType *Q=new elemType(MaxLength);" 应改为 Q=new elemType[MaxLength]; //方括号！

Q在这里不能重新声明，否则会覆盖类的Q；根本没有为Q申请到空间，只是为EnQueue的Q申请了空间。

还有哦！动态分配了内存，结束时是应该释放这些内存的。

[5311]

#include <iostream > 
using namespace std; 
#define MaxLength 6 
typedef int elemType; 

class Queue 
{ 
public: 
	Queue(); 
	virtual ~Queue();		//增加个析构函数
	int QueueLength(); 
	void EnQueue(elemType e); 
	int DeQueue(elemType &e); 

protected: 
	elemType *Q; 
	elemType front; 
	elemType rear; 
	elemType counter; 
	elemType a[MaxLength]; 


}; 

Queue::Queue() 
{ 
	Q = new elemType[ MaxLength ];	//修改此处
	if(!Q) 
		return ; 
	front = rear=0; 
	counter = 0; 
} 

Queue::~Queue()
{
	if (Q)
	{
		delete [] Q;
	}
}


int Queue::QueueLength() 
{ 
	return counter; 
} 


void Queue::EnQueue(elemType e) 
{ 
	if(counter == MaxLength) 
		return ; 
	Q[rear] = e; 
	rear = (rear + 1)%MaxLength; 
		counter++; 

} 


int Queue::DeQueue( elemType &e) 
{ 
	if(counter == 0) 
		return 1; 
	e= Q[front]; 
	front = (front + 1)%MaxLength; 
	counter--; 
	return e; 
} 

int main() 
{ 
    Queue a; 
	int Length = 0; 
	Length = a.QueueLength(); 
	cout <<Length; 
	a.EnQueue(12); 
	int LE = 0; 
	LE = a.QueueLength(); 
	cout <<LE; 
	return 0; 
}