从txt文件读入链表

Question

我正在尝试将 *.txt 文件中的数据读取到链接列表中。该文件设置了 16 种不同类型的数据，这些数据排列成行，每种数据类型之间都有选项卡。我有几个问题。编译器没有给出错误，但是当我运行程序并输入要读取的文件名时，什么也没有发生。我尝试用 for 循环 for(int i=0; i<NUM_LINES; i++) 替换 while(!din.eof()) 行（下面的第 27 行），这似乎有帮助，但我得到了前三个元素（所有字符串类型），后跟一行零，这一行重复直到循环结束。我已经包含了我认为问题所在的方法。我想知道是否有人可以查看我的代码并让我知道问题出在哪里。谢谢。

#include <iostream>
#include <fstream>
using namespace std;

class Node
{
 public:
   // Constructors
   Node();
   Node(const string name, const string position, const string team, const int g, const int att, const float attg, const int cmp, const float pct, const int yds, const float ydsg, const int lng, const int td, const int inte, const int sck, const int sckyl, const float rating);
   Node(const Node & node);
   ~Node();

   // Methods
   bool readData();
   void setNext(Node* next);
   void print() const;

 private:
   string Name;
   string Position;
   string Team;
   int G;
   int Att;
   float AttG;
   int Cmp;
   float Pct;
   int Yds;
   float YdsG;
   int Lng;
   int TD;
   int Int;
   int Sck;
   int SckYL;
   float Rating;
   Node *Next;
};

//----------------------------------------------
// Constructor method
//----------------------------------------------
Node::Node()
{
   Name = "";
   Position = "";
   Team = "";
   G = 0;
   Att = 0;
   AttG = 0.0;
   Cmp = 0;
   Pct = 0.0;
   Yds = 0;
   YdsG = 0.0;
   Lng = 0;
   TD = 0;
   Int = 0;
   Sck = 0;
   SckYL = 0;
   Rating = 0.0;
   Next = NULL;
}

//----------------------------------------------
// Constructor method with parameters
//----------------------------------------------
Node::Node(const string name, const string position, const string team, const int g, const int att, const float attg, const int cmp, const float pct, const int yds, const float ydsg, const int lng, const int td, const int inte, const int sck, const int sckyl, const float rating)
{
   Name = name;
   Position = position;
   Team = team;
   G = g;
   Att = att;
   AttG = attg;
   Cmp = cmp;
   Pct = pct;
   Yds = yds;
   YdsG = ydsg;
   Lng = lng;
   TD = td;
   Int = inte;
   Sck = sck;
   SckYL = sckyl;
   Rating = rating;
   Next = NULL;
}

//----------------------------------------------
// Copy constructor method
//----------------------------------------------
Node::Node(const Node & node)
{
   Name = node.Name;
   Position = node.Position;
   Team = node.Team;
   G = node.G;
   Att = node.Att;
   AttG = node.AttG;
   Cmp = node.Cmp;
   Pct = node.Pct;
   Yds = node.Yds;
   YdsG = node.YdsG;
   Lng = node.Lng;
   TD = node.TD;
   Int = node.Int;
   Sck = node.Sck;
   SckYL = node.SckYL;
   Rating = node.Rating;
   Next = NULL;
}

//----------------------------------------------
// Destructor method
//----------------------------------------------
Node::~Node()
{
}

//----------------------------------------------
// Method:   readData
// Purpose:  Read data from file into linked list, and print contents of the list.
//----------------------------------------------
bool Node::readData()
{
   // Declare local variables
   string name, position, team;
      name = position = team = "";
   int g, att, cmp, yds, lng, td, inte, sck, sckyl;
      g = att = cmp = yds = lng = td = inte = sck = sckyl = 0;
   float attg, pct, ydsg, rating;
      attg = pct = ydsg = rating = 0.0;

   // Get file name
   string filename = "";
   cout << "Enter file name: ";
   cin >> filename;

   // Open input file
   ifstream din;
   din.open(filename.c_str());
   if (din.fail())
   {
      cerr << "Could not open file: " << filename << endl;
      return false;
   }

   // Read data
   Node *head = NULL;
   while (!din.eof())
   {
      din >> name >> position >> team >> g >> att >> attg >> cmp >> pct >> yds >> ydsg >> lng >> td >> inte >> sck >> sckyl >> rating;

      Node *temp = new Node(name, position, team, g, att, attg, cmp, pct, yds, ydsg, lng, td, inte, sck, sckyl, rating);
      temp->setNext(head);
      head = temp;
   }

   din.close();
   head->print();
   return true;
}

//----------------------------------------------
// setNext method
//----------------------------------------------
void Node::setNext(Node* next)
{
   Next = next;
}

//----------------------------------------------
// Print method
//----------------------------------------------
void Node::print() const
{
   cout << Name << "    " << Position << "    " << Team << "    " << G << "    " << Att << "    " << AttG << "    "
        << Cmp << "    " << Pct << "    " << Yds << "    " << YdsG << "    " << Lng << "    " << TD << "    " << Int << "    "
        << Sck << "    " << SckYL << "    " << Rating;
   if (Next != NULL)
      Next->print();
}

//----------------------------------------------
// Main program
//----------------------------------------------

int main()
{
   Node list;
   if (list.readData())
      cout << "Success" << endl;
   else
      cout << "Fail" << endl;

   return 0;
}

Answer 1

在你的文件中，Charlie Batch 等等。 当你读到它时，你认为会发生什么？ 名称将变为Charlie；位置将变为Batch。

发生这种情况是因为在遇到空格之前读取数据。

http://cplusplus.com/reference/fstream/fstream/?kw=fstream

Answer 2

您是否尝试过启动循环？获取文件的第一行，然后执行您的 while 语句。在 while 语句中，创建新节点，然后获取下一行。在那里结束循环的代码块。

// Read data
Node *head = NULL;

  din >> name >> position >> team >> g >> att >> attg >> cmp >> pct >> yds >> ydsg >> lng >> td >> inte >> sck >> sckyl >> rating;

while (!din.eof())
{

  Node *temp = new Node(name, position, team, g, att, attg, cmp, pct, yds, ydsg, lng, td, inte, sck, sckyl, rating);
  temp->setNext(head);
  head = temp;

  din >> name >> position >> team >> g >> att >> attg >> cmp >> pct >> yds >> ydsg >> lng >> td >> inte >> sck >> sckyl >> rating;

}