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我正在尝试从文本文件中逐字阅读（并跟踪行号 - 这就是我使用 getline 但这是一个单独的问题的原因）并重复文件的最后一行。我认为这是因为我正在使用 getline() 但我每次都设置一个新节点但是当我 displayAll() 它只打印文件的最后一行。（底部的一些文件和错误示例）。我包括了 Node 类，因为它与这个问题最相关，而 LinkedListOfFiles 主要是支持创建后的完整单词列表的函数。

class Node
{
public:

    string getNode(){return node;}
    void setNode(string s){node=s;}
    string getFile(){return file;}
    void setFile(string s){file=s;}
    int getNodeNumber(){return nodeNumber;}
    void setNodeNumber(int ln){if(ln<0)ln=0;nodeNumber=ln;}

    friend class LinkedListOfFiles;

    int number;
    char name; 
    Node * next;

    Node() {pLeft=NULL;pRight=NULL;}
    Node(Node * pS) {pLeft=NULL;pRight=NULL;pData=pS;}
    friend class BSTOfWords;
private:
    Node * pData;
    Node * pLeft;
    Node * pRight;

    //Node * pData;
    Node * pNext;
    Node * pPrev;
    string node;
    string file;
    int nodeNumber;
};




void LinkedListOfFiles::addFile(string fileName)
{
    int line = 0;
    ifstream InputFile;
    InputFile.open (fileName);
    string w = "",next;
    Node * wnode = new Node;
    (*wnode).setFile(fileName);

    while (!InputFile.eof())
    {
        getline(InputFile,next);
        (*wnode).setNode(next);
        line++;
        if (next == "\n"){cout<<"eof found! \n";}
        (*wnode).setNodeNumber(line);
        putAtFront (wnode);
        cout << (*wnode).getFile()+"  "+intToString((*wnode).getNodeNumber())+" "+(*wnode).getNode()+" \n";
        Node * wnode = new Node;
        wnode->pData = wnode->pNext;
    }
    //cout << " outbound to file list: "+(*wnode).getFile()+" \n";
}


void LinkedListOfFiles::putAtFront(Node * ps )
{
    insert(ps,pFront);
}


void LinkedListOfFiles::insert(Node * pNewWords, Node * pFound)
{
    Node * pNewNode;
    pNewNode = new Node;
    (*pNewNode).pData=pNewWords;

    (*((*pFound).pNext)).pPrev=pNewNode;
    (*pNewNode).pNext=(*pFound).pNext;
    (*pNewNode).pPrev=pFound;
    (*pFound).pNext=pNewNode;
}

string LinkedListOfFiles::displayAll()
{
    string result;

    // pointer to current node
    Node * pCurrentNode;

    // make current node the first item in list
    pCurrentNode = (*pFront).pNext;  //pFront points to the sentinal, it's pNext points to the first item in list

    while((*pCurrentNode).pData != NULL)
    {
        result+= (*((*pCurrentNode).pData)).getFile(); //add the currrent node's fileName
        result+="   ";
        result+= intToString((*((*pCurrentNode).pData)).getNodeNumber()); //add the currrent node's lineNumber
        result+="   ";
        result+= (*((*pCurrentNode).pData)).getNode(); //add the currrent node's line of text
        result+="   ";

        result+= "\n";
        pCurrentNode = (*pCurrentNode).pNext;
    }

    return result; // return the string with all the data
}

这是一个文件和它会生成的错误示例

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favour fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.

错误是

test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.
test.txt   9   And would suffice.

我现在正在尝试学习 C++ 和链表。这些可能是相似的（如果它们可以帮助您查看此问题）来自文本文件的链接列表 想要读取超过 50,000 个 txt 文件并将它们保存在 C++ 中的链接列表中， 但它们不同，因为我可能没有正确使用指针来保存每个我前进的节点（一些指针可能指向自我）。

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1 回答 1

1

addFile 函数中的循环应该是：

while(getline(InputFile, next).good())
{
    // do stuff
}

如果 getline 到达文件末尾，则 next 中的值将保持不变。这可能是重复线路的原因。

于 2013-04-09T05:35:02.577 回答