我刚刚使用堆栈完成了Post Fix Notation（RPN）项目。我对一些编译器错误没有太多好运，所以当我在我身边进行调试时，我会来找你们。
此文件提供给我们。我们假设从中派生出一个堆栈类。
#ifndef ABSTRACTSTACK_H
#define ABSTRACTSTACK_H
#include <string>
using namespace std;
/* --------------- Class 'Oops' ---------------
Class
Thrown when an error is encountered.
Member 'm_msg' stores an error message.
*/
class Oops
{
string m_errormsg;
public:
Oops(string msg) : m_errormsg(msg) {}
const string& getMsg() const
{
return m_errormsg;
}
};
/* --------------- Abstract Class AbstractStack --------------- */
template < typename T >
class AbstractStack
{
public:
// Purpose: Checks if a stack is empty
// Returns: 'true' if the stack is empty
// 'false' otherwise
virtual bool isEmpty() const = 0;
// Purpose: looks at the top of the stack
// Returns: a const reference to the element currently on top of the stack
// Exception: if the stack is empty, THROW a 'Oops' object with an error message!!!
virtual const T& top() const throw ( Oops ) = 0;
// Purpose: push an element into the stack
// Parameters: x is the value to push into the stack
// Postconditions: x is now the element at the top of the stack,
virtual void push(const T& x) = 0;
// Purpose: pop the stack
// Postconditions: the element formerly at the top of the stack has
// been removed
// Note: Poping an empty stack results in an empty stack.
virtual void pop() = 0;
// Purpose: clears the stack
// Postconditions: the stack is now empty
virtual void clear() = 0;
};
#endif
这是我的派生类及其实现。
#ifndef STACK_H
#define STACK_H
#include<string>
#include<iostream>
#include<cstdlib>
#include "abstractstack.h"
using namespace std;
template<typename T>
struct Node
{
T Data;
Node<T>* next;
};
template<typename T>
class Stack : public AbstactStack<T>
{
private:
Node<T>* Top;
public:
//Purpose: Destructor
//Postconditions: The stack is now empty
~Stack() {};
//Purpose: Default Constructor
//Postconditions: Top is initialized to 'NULL'
Stack(); Top(NULL){};
//Overloaded = Operator
//Postconditions: *this is now equal to rhs
const Stack<T>& operator = (const Stack<T>& rhs);
//Purpose: Check if a stack is empty
//Returns: 'true' if the stakc is empty, 'false' otherwise
bool isEmpty() const;
//Purpose: Looks at the top of the stack
//Returns: a const reference to the element currently on top of the stack
//Exception: if the stack is empty, THROW a 'Oops' object with an error message!!!"
const T& top() const throw(Oops);
//Purpose: push an element into the stack
//Parameters: x is the value to push into the stack
//Postconditions: x is now the element at the top of the stack
void push(const T& x);
//Purpose: pop the stack
//Postconditions: the element formerly at the top of the stack has been removed
//Popping an empty stack results in an empty stack
void pop();
//Purpose: clears the stack
//Postconditions: the stack is now empty
void clear();
//Reverses the stack
//Postconditions: stack is now in reverse order
void reverse();
};
#include "stack.hpp"
#endif
实施（.hpp）
#include <string>
#include <iostream>
using namespace std;
template<typename T>
const Stack<T>& Stack<T>::operator = (const Stack<T>& rhs)
{
if (this != &rhs)
{
if (Top != NULL)
clear();
Node<T>* rhsPtr = rhs.Top;
Node<T>* copyPtr = Top = new Node<T>;
copyPtr->Data = rhsPtr->Data;
while (rhsPtr->next != NULL)
{
rhsPtr = rhsPtr->next;
copyPtr->next = new Node<T>;
copyPtr = copyPtr->next;
copyPtr->Data = rhsPtr->Data;
}
copyPtr->next = NULL;
}
return(*this)
}
template<typename T>
Stack<T>::Stack(const Stack<T>& rhs)
{
Top = NULL;
*this = rhs;
}
template<typename T>
bool Stack<T>::isEmpty()
{
return(Top == NULL);
}
template<typename T>
const T& top() const throw(Oops)
{
if (Top != NULL)
return(Top->Data);
else
throw Oops(Stack is Empty!);
}
template<typename T>
void Stack<T>::push(const T& x)
{
Node<T>* newNode = new Node;
newNode->Data = x;
if (isEmpty())
{
Top = newNode;
return;
}
newNode->next = Top;
Top->next = newNode;
}
template<typename T>
void Stack<T>::pop()
{
Node<T>* temp;
if (Top != NULL)
{
temp = Top;
Top = Top->next;
delete temp;
}
}
template<typename T>
void Stack<T>::clear()
{
Node<T>* temp;
while (Top != NULL)
{
temp = Top;
Top = Top->next;
delete temp;
}
}
template<typename T>
void Stack<T>::reverse()
{
Node<T>* current;
Node<T>* previous;
Node<T>* next;
previous = NULL;
current = Top;
while (current != NULL)
{
next = current->next;
current->next = previous;
previous = current;
current = next;
}
Top = previous;
}
编译器对我的Stack类不满意。 “stack.h：25：34：错误：在'＆lt;'标记之前预期的模板名称 class Stack：public AbstactStack
我被告知我不能继承Abstract，因为它不是一个类，但我的教授告诉我它很好，我应该在Stack的.cpp中添加一个前向声明，但我不确定这样。我知道我还没有完成，但我希望能够至少解决这个错误，所以我可以看看我的程序是否正常工作。
我将我的主程序发布到Pastebin中，其标题和实现在这里以备不时之需。 http://pastebin.com/1t2YGa2c
答案 0 :(得分：3)
在我看来，您遇到的问题只是以下几行中的拼写错误：
class Stack : public AbstactStack<T>
将AbstactStack<T>更改为AbstractStack<T>，这应该有效。
您获得的错误解释了字符<之前的类名应该是模板，但由于您在类的名称中输入了错字，因此无法识别。
确保您阅读并理解错误消息！在解决这些问题时，它们通常非常有用。
小方注意：如果您查看错误消息，则会看到错误所在的文件名，后跟行号和列号（stack.h:25:34）。调试时非常有用的信息。