2013-03-11 161 views
1

因此对于我的指派,我们必须修改堆栈类并对其进行测试。我已经成功地添加了所有必要的方法,但是我坚持的是在展示它时如何最好地打印出堆栈中的内容。所以基本上,我要用随机数据填充堆栈并测试我实现的各种方法,但是我不知道如何将堆栈打印到控制台以显示我已经完成了我应该做的事情。我知道这是一个非常基本的问题,但我只是卡在这里。我猜我必须以某种方式使用方法getTop,但是如何使用它来打印堆栈中的内容。这里是我的所有文件:如何在C++中打印堆栈

StackP.cpp

#include <cassert> 

    using namespace std; 

    #include "StackP.h" 

    Stack::Stack() 
     : topPtr(0) { 
    } 

    Stack::Stack(const Stack& aStack) 
     throw(OutOfStorageException) { 

     // Original list is empty 
     if (aStack.topPtr == 0) { 
      topPtr = 0; 
     } 
     else { 
      try { 
       // Copy first node 
       topPtr = new StackNode; 
       topPtr->item = aStack.topPtr->item; 

       // Copy rest of list 
       StackNode* newPtr = topPtr; // Pointer to new list 
       for (StackNode* origPtr = aStack.topPtr->next; 
        origPtr != 0; 
        origPtr = origPtr->next) { 
       newPtr->next = new StackNode; 
       newPtr = newPtr->next; 
       newPtr->item = origPtr->item; 
       } 

      newPtr->next = 0; 
      } 
      catch (const bad_alloc&) { 
      // Release all memory successfully allocated in this copy 
       while (!isEmpty()) { 
       pop(); 
       } 
       throw OutOfStorageException("Out of memory"); 
      } 
     } 
    } 

    Stack::~Stack() { 

     // Pop until stack is empty 
    while (!isEmpty()) {        
     pop(); 
    } 
    assert(topPtr == 0); 
} 

bool Stack::isEmpty() const { 

    return topPtr == 0; 
} 

void Stack::push(const StackItemType& newItem) 
    throw(OutOfStorageException) { 

    try { 
     StackNode* newPtr = new StackNode; 

     newPtr->item = newItem; 

     newPtr->next = topPtr; 
     topPtr = newPtr; 
    } 
    catch (const bad_alloc&) { 
     throw OutOfStorageException("Out of memory"); 
    } 
    } 
} 

void Stack::pop() 
    throw(OutOfDataException) { 

    if (isEmpty()) { 
     throw OutOfDataException("Cannot pop an empty stack."); 
    } 
    StackNode* temp = topPtr; 
    topPtr = topPtr->next; 

    temp->next = 0; // safeguard 
    delete temp; 
} 

void Stack::pop(StackItemType& stackTop) 
    throw(OutOfDataException) { 

    if (isEmpty()) { 
     throw OutOfDataException("Cannot pop an empty stack."); 
    } 
    stackTop = topPtr->item; 
    StackNode* temp = topPtr; 
    topPtr = topPtr->next; 

    temp->next = 0; // safeguard 
    delete temp; 
} 

void Stack::getTop(StackItemType& stackTop) const 
    throw(OutOfDataException) { 

    if (isEmpty()) { 
     throw OutOfDataException("Cannot get the top of an empty stack."); 
    } 
    stackTop = topPtr->item; 
} 

    void Stack::popAndDiscard(int count) { 

    while (count>0 && !isEmpty()) { 

     pop(); 
     count--; 
     }//end while 

    }// end popAndDiscard 

StackP.h:

#ifndef STACKP_H 
#define STACKP_H 1 

#include "OutOfStorageException.h" 
#include "OutOfDataException.h" 

typedef int StackItemType; 

class Stack { 
public: 

    Stack(); 

    Stack(const Stack& aStack) 
     throw(OutOfStorageException); 

    ~Stack(); 

    bool isEmpty() const; 

    void push(const StackItemType& newItem) 
     throw(OutOfStorageException); 

    void pop() 
     throw(OutOfDataException); 

    void pop(StackItemType& stackTop) 
     throw(OutOfDataException); 

    void getTop(StackItemType& stackTop) const 
     throw(OutOfDataException); 

    void popAndDiscard(int count); 


private: 

    struct StackNode { 
     StackItemType item; 

     StackNode* next; 
    }; 

    StackNode* topPtr; 
}; 

    #endif 

预先感谢您的帮助!

+4

一般情况下,你不能检查堆栈,除非你也消耗它。这是它的重点。 – 2013-03-11 19:55:26

+0

欢迎来到Stack Overflow。出于各种原因,家庭作业标签不鼓励。 – 2013-03-11 19:55:35

+2

欢迎来到Stack Overflow。请将您的代码降低到显示您的问题所需的最低限度。谢谢。 – thiton 2013-03-11 19:56:18

回答

2

您应该添加打印功能@WhozCraig建议:

void print(std::ostream& os) 
{ 
    StackNode* current = topPtr; 
    while(current != NULL) 
    { 
     os<<current->item<< " "; 
     current = current->next; 
    } 
} 

不要忘记#include <ostream>