--------------------- Queue.h ------------ --------C++:[class]未在此範圍內聲明
#ifndef QUEUE_H
#define QUEUE_H
#include <iostream>
#include "MyException.h"
using namespace std;
template<class T>
class Queue;
template<class T>
ostream& operator<<(ostream&,Queue<T>&);
template<class T>
class Queue
{
public:
friend ostream& operator<< <T>(ostream&,Queue<T>&);
Queue();
Queue(const Queue<T>& other);
Queue<T>& operator=(const Queue<T>& other);
~Queue();
void enqueue(const T& el);
T dequeue();
void increasePriority(const T& el);
bool isEmpty();
private:
class Node
{
public:
Node(const T& data, Node* n = 0)
{
element = data;
next = n;
}
T element;
Node* next;
};
Node* head;
};
#include "Queue.C"
#endif
我們不允許更改.h(above)文件。
--------------------- Queue.C --------------------
#include "Queue.h"
template<class T>
ostream& operator << (ostream &strm, Queue<T> &obj)
{
if (obj.isEmpty())
{
strm << "[]";
return strm;
}
else
{
strm << '[';
//line 28
Node* tmp = new Node();
tmp = obj.head;
strm << tmp.element + ',';
while (tmp->next != 0)
{
tmp = tmp->next;
if (tmp-next != 0)
{
strm << tmp.element + ',';
}
else
{
strm << tmp.element;
}
}
strm << ']';
delete [] tmp;
tmp = 0;
return strm;
}
return strm;
}
//...more code
Queue::Queue()
{
//line 54
head = new Node();
}
於是從一些代碼我收到錯誤如下:
Queue.C: In function ‘std::ostream& operator<<(std::ostream&, Queue<T>&)’:
Queue.C:28: error: ‘Node’ was not declared in this scope
Queue.C:28: error: ‘tmp’ was not declared in this scope
Queue.C:28: error: expected type-specifier before ‘Node’
Queue.C:28: error: expected ‘;’ before ‘Node’
Queue.C:34: error: ‘next’ was not declared in this scope
Queue.C: At global scope:
Queue.C:54: error: ‘head’ was not declared in this scope
Queue.C:54: error: expected type-specifier before ‘Node’
Queue.C:54: error: expected ‘;’ before ‘Node’
'Node'是'Queue'的一部分。 – chris 2013-02-25 06:49:51
由於源文件包含在頭文件中,因此不需要將頭文件包含在源文件中。 – 2013-02-25 06:52:17