从文件读取时遇到问题。似乎过早达到EOF

Question

我确信这个问题可以相对容易地解决，但我正在努力寻找问题。 我的代码只是读取文件中的所有单词，然后将每个单词，单词位置，句子的开始和结束存储在一个数组中。数组输出到另一个文本文件。

我可以阅读所有信息，直到最后一句，然后我有一个错误。有什么想法吗？

/** 
* Programmer: fryeguy 
* Course: 
* Program: TxtCrawl for MicroSearch 
* 
* Algorithm: 
* TxtCrawl is the component of MicroSearch that reads text 
* documents for search terms and stores them for 
* indexing 
* 
* 1. Count words in doc, then initialize 
*  wordsFromDoc array to wordCount 
* 2. Initiate output file for writing. 
* 3. Open input file for reading words. 
* 4. Until reaching EOF: 
*  4.a. Set value for start "get pointer" in startSentence (.tellg()). 
*  4.b. Store value for end "get pointer" in endSentence (.tellg()). 
*  4.c. Reset "get pointer" to startSentence location. 
*  4.d. Until reaching endSentence, Read into the 
*   array theWord, wordPos, startSent, and endSent 
* 5. Write wordsFromDoc array to file 
* 6. When EOF is reached close the files. 
*/ 

#include <iostream> 
#include <iomanip> 
#include <fstream> 
#include <string> 

using namespace std; 

struct wordProps  // stores word info to be placed in array 
{ 
    string theWord; // stores the word 
    int  wordPos; // stores the position of word 
    int  startSent; // stores the start point of the sentence 
    int  endSent; // stores the end point of the sentence 
}; 

void countWords(string, int&, int&); 

int main() 
{ 

    ifstream iFile; // file stream for reading in data 
    ofstream oFile; // file stream for writing data 

    string iFileName = "TextFile2.txt"; // name of test file to read from 
    string oFileName = "OutputFile.txt"; // name of test file to write to 
    string aLine = "";      // stores a line preceeding a newline character (\n) 
    string aWord = "";      // stores words from doc for indexing 
    int  charCount = 0;     // count of characters in doc 
    int  wordCount = 0;     // count of words in doc 
    int  aLineWordCount = 0;    // count of words in a single line being processed 
    int  wordBegin = 0;     // stores location of word in doc 
    int  startSentence = 0;    // stores pointer value for start of sentence 
    int  endSentence = 0;    // stores pointer value for end of sentence 

    /** 
    * 1. Count words in doc, then initialize 
    * wordsFromDoc array to wordCount 
    */ 
    countWords(iFileName, charCount, wordCount); 
    cout << "charCount: " << charCount << endl; // DEBUG CODE 
    cout << "wordCount: " << wordCount << endl; // DEBUG CODE 
    wordProps wordsFromDoc[wordCount]; 
    cout<< "length of array: " << (sizeof(wordsFromDoc)/sizeof(*wordsFromDoc)) << endl; // DEBUG CODE 

    /** 
    * 2. Initiate output file for writing 
    */ 
    oFile.open (oFileName.c_str()); // setup output file and write header 
    oFile << setw(20) << left << "File Name: " << iFileName << endl; 
    oFile << setw(20) << "---------------------------------------" << endl << endl; 

    /** 
    * 3. Open input file for reading words 
    */ 
    iFile.open (iFileName.c_str()); 
    if (!iFile.is_open()) 
     cout << "No such file exists!" << endl; 
    else 
    { 
     /** 
     * 4. Until reaching EOF: 
     */ 
     // I have been attempting different counting methods assuming the eof was being reached prematurely 
     // The results really have not varied with this code 
     // while (iFile.tellg() != charCount) 
     while (!iFile.eof()) 
     { 
      //cout << "count: " << count << endl; 
      /** 
      * 4.a. Set value for start "get pointer" in startSentence (.tellg()). 
      */ 
      startSentence = iFile.tellg(); 
      cout << "startSentence: " << startSentence << endl; // DEBUG CODE 

      /** 
      * 4.b. Store value for end "get pointer" in endSentence (.tellg()). 
      */ 
      getline(iFile, aLine, '.'); 
      cout << aLine << endl; // DEBUG CODE 
      endSentence = iFile.tellg(); 
      aLine.clear(); 
      cout << "endSentence: " << endSentence << endl; // DEBUG CODE 

      if (!iFile.is_open()) 
      { 
       cout << "The if, iFile.tellg(): " << iFile.tellg() << endl; // DEBUG CODE 
       iFile.close(); 
       iFile.open (iFileName.c_str()); 
      } 

      /** 
      * 4.c. Reset "get pointer" to startSentence location. 
      */ 
      iFile.seekg(startSentence); 
      cout << "iFile.tellg(): " << iFile.tellg() << endl; // DEBUG CODE 

      /** 
      * 4.d. Until reaching endSentence, Read into the 
      *  array theWord, wordPos, startSent, and endSent 
      */ 

      // As the last line is about to be read there is an error of some sort. 
      // My guess is that somehow I exceed the end of the file but my startSentence 
      // and endSentence variables are pointing where I think they should. 

      for (; iFile.tellg() < endSentence; aLineWordCount++) 
      { 
       wordsFromDoc[aLineWordCount].wordPos = iFile.tellg(); 
       cout << "wordPos: " << wordsFromDoc[aLineWordCount].wordPos << endl; // DEBUG CODE 
       iFile >> wordsFromDoc[aLineWordCount].theWord; 
       cout << "theWord: " << wordsFromDoc[aLineWordCount].theWord << endl; // DEBUG CODE 
       wordsFromDoc[aLineWordCount].startSent = startSentence; 
       cout << "startSent: " << wordsFromDoc[aLineWordCount].startSent << endl; // DEBUG CODE 
       wordsFromDoc[aLineWordCount].endSent = endSentence; 
       cout << "endSent: " << wordsFromDoc[aLineWordCount].endSent << endl << endl; // DEBUG CODE 
       cout << "aLineWordCount: " << aLineWordCount << endl; 
      } // end for 

     } // end while !=iFile.eof 

      // THIS section of code is never reached because of the hang up above. 
      /** 
      * 5. Write wordsFromDoc array to file 
      */ 
      for (int count = 0; count < aLineWordCount; count++) 
      { 
       oFile << setw(20) << left 
       << wordsFromDoc[count].theWord << " " 
       << wordsFromDoc[count].wordPos << " " 
       << wordsFromDoc[count].startSent << " " 
       << wordsFromDoc[count].endSent << endl; 
      } 

    } // end else 

    /** 
    * 6. When EOF is reached close the files. 
    */ 
    iFile.close(); 
    oFile.close(); 

// DEBUG CDODE for verifying results 
// for (int count = 0; count < wordCount; count++) { 
//  cout << "theWord: " << wordsFromDoc[count].theWord << endl; 
//  cout << "wordPos: " << wordsFromDoc[count].wordPos << endl; 
//  cout << "startSent: " << wordsFromDoc[count].startSent << endl; 
//  cout << "endSent: " << wordsFromDoc[count].endSent << endl << endl; 
// } 

} 

/** 
* Implement countWords function 
*/ 
void countWords(string theFileName, int &charCount, int &wordCount) 
{ 
    string theWord = ""; 
    char theChar = ' '; 
    fstream inFile; 

    //count the chars 
    inFile.open (theFileName.c_str()); 
    if (!inFile.is_open()) 
     cout << "No such file exists!" << endl; 
    else 
    { 
     inFile.get(theChar); 
     while (!inFile.eof()) 
     { 
      charCount++; 
      inFile.get(theChar); 
     } 
    } 
    inFile.close(); 

    // count the words 
    inFile.open (theFileName.c_str()); 
    if (!inFile.is_open()) 
     cout << "No such file exists!" << endl; 
    else 
    { 
     while (!inFile.eof()) 
     { 
      inFile >> theWord; 
      wordCount++; 
     } 
    } 
    inFile.close(); 
} 

Answer 1

的IStream

我检查。 Istream没有化身得到或getline 一次处理多个分隔符1。其他人也有同样的问题2。逐字符IO是最实用的解决方案。其他解决方案涉及编码当前Istream方法的增强版本 。

构想

1. 阅读完整的文件到内存中一次。
2. 删除换行符（任何CR或LF）。
3. 拆分文档到在每个特殊 句号分隔符，结束放置一个一致的标记（LF或ETX“\ 003”）行，每行的分隔符后，一边写文档回到磁盘。
4. 现在文档可以照常处理;但是使用周期的已知标记代替 作为分隔符。
5. 删除包含重新定界文档的临时文件。

立即读取整个文件不是问题，因为最终反正都在 内存中;将文字全部放在一起的字符串 等于整个文档。一旦重新定界的文件被写入磁盘，内存就可以被释放。

注意

1的IStream ::获得
2与函数getline（在代码大师讨论）多定界符