Thread: Deleting Text File Record

Hello,
I am trying to write a function that searches for, and deletes, a particular record in a text file. I am trying to achieve this by creating a temporary file, copy everything except the record i want to delete, delete the original file, and then rename the temp file using the original name. However, my code does not delete the record, and instead, sometimes copies the contents of the original file and appends.

Can anyone tell me where I went wrong, or show me a better way. Thanks in advance.

Code:

void POS::deleteRecord(char fileName[], string itemNum) 
{                                            
 ofstream write;
 ifstream read;
 
 counter = 0;
   
 string num, name, manu, type, reso, cost, pric, quan;
   
 read.open(fileName); 

 write.open("temp.txt", ios::out);
 
 write << ""; // empty the file just in case;
  
   getline(read, num);
   getline(read, name);
   getline(read, manu);
   getline(read, type);
   getline(read, reso);
   getline(read, cost);
   getline(read, pric);
   getline(read, quan);
   getline(read, readSpace);
  
 while (!read.fail())
 {
                  
       if (itemNum.compare(num)== 0) // is item number == to our search item?
       {
         
          num = "";
          name = "";
          manu = "";
          type = "";
          reso = "";
          cost = "";
          pric = "";
          quan = "";
          readSpace = "";
          
         continue; // skip and move to the next record      
          
                
       }
       else
       {
           
            counter++;        
           // store only valid records (quantity > 0)
           write << counter << endl
                 << name << endl
                 << manu << endl
                 << type << endl
                 << reso << endl
                 << cost << endl
                 << pric << endl
                 << quan << endl
                 << endl; 
       }// end else
       
       getline(read, num);
   getline(read, name);
   getline(read, manu);
   getline(read, type);
   getline(read, reso);
   getline(read, cost);
   getline(read, pric);
   getline(read, quan);
   getline(read, readSpace);
             
 }// end while
  
 
 read.close();
 write.close();
 
 // delete the original file 
 remove (fileName);
 
 int result;
 
 // rename the temp file to original name
 result = rename("temp.txt", "Printers.txt");
  
 if (result == 0)
 cout << "  Successfully!";
 else
 cout << "  Unsuccessful!";
 
 remove("temp.txt");
  
 // reset counters
 counter = 0;
 
      
}

I also tried vectors but now I am getting a "Permission Denied" error message and now every time I try to rerun the program, it just freezes! Any suggestions will be greatly appreciated.

Code:

# include <iostream>
# include <vector>
# include <fstream>
# include <algorithm>

using namespace std;

int main()
{
  ifstream infile;
  ofstream outfile;
  
  int counter = 0;
  
  string searchItem;
  
  cout << "Enter search Item: ";
  cin >> searchItem;
  
  infile.open("test.txt");
  outfile.open("outfile.txt");
  outfile << "";
  
  vector<string> info(9);  
   
  getline(infile, info[0]);
   getline(infile, info[1]);        
   getline(infile, info[2]);
   getline(infile, info[3]);
   getline(infile, info[4]);
   getline(infile, info[5]);        
   getline(infile, info[6]);
   getline(infile, info[7]);
   getline(infile, info[8]);// space
   
  while (!infile.fail())
  {
      
   if (info[0].compare(searchItem) == 0)
      info.erase(info.begin(), info.begin()+8);    
   else
   {
    counter++;
    
    outfile << counter << endl
            << info[1] << endl
            << info[2] << endl
            << info[3] << endl
            << info[4] << endl
            << info[5] << endl
            << info[6] << endl
            << info[7] << endl
            << info[8] << endl; // output a space   
   }
   
    getline(infile, info[0]);
   getline(infile, info[1]);        
   getline(infile, info[2]);
   getline(infile, info[3]);
   getline(infile, info[4]);
   getline(infile, info[5]);        
   getline(infile, info[6]);
   getline(infile, info[7]);
   getline(infile,info[8]);
   
  }// end while
   
   infile.clear();
  infile.seekg(0);  
  infile.close(); 
  outfile.close();
      
system ("pause");    
}

Thanks for your reply DWK. I found the reason why my original file kept growing: I had a function call that had some faulty code in it. Any way I got it to delete with the following code. Please feel free to suggest a more effecient or better solution. Thanks again.

Code:

void POS::deleteRecord(char fileName[], string itemNum)
{                                                      
    
   // objects for writing and reading
   ofstream write; 
   ifstream read;
   
   counter = 0; // used for renumbering records after deletion
   
   // variables for storing record details
   string num, name, manu, type, reso, cost, pric, quan;
      
   write.open("temp.txt", ios::out); // open temp file for storing valid records
   write << ""; // empty file just in case.
   
   read.open("Printers.txt"); // open file for reading
   
   // read first record on file
   getline(read, num);
   getline(read, name);
   getline(read, manu);
   getline(read, type);
   getline(read, reso);
   getline(read, cost);
   getline(read, pric);
   getline(read, quan);
   getline(read, readSpace); // store space as well
   
   // read file until no more records exist
   while(!read.fail()) 
   {
    if (itemNum.compare(num)== 0) // if record's num equals our search item
    {
     // delete record
     num.erase(num.begin(), num.end()); // delete every character of record
     name.erase(name.begin(), name.end());
     manu.erase(manu.begin(),manu.end());
     type.erase(type.begin(),type.end());
     reso.erase(reso.begin(),reso.end());
     cost.erase(cost.begin(),cost.end());
     pric.erase(pric.begin(),pric.end());
     quan.erase(quan.begin(),quan.end());
     

                                    
    }// end if
    else // else store only valid records (quantity > 0)
    {
         counter++; // new item counter 
                      
           write << counter << endl // insert new item numbering
                 << name << endl
                 << manu << endl
                 << type << endl
                 << reso << endl
                 << cost << endl
                 << pric << endl
                 << quan << endl
                 << endl; // inserts a space between records
         
        
    }// end else
    
    // read another record
   getline(read, num);
   getline(read, name);
   getline(read, manu);
   getline(read, type);
   getline(read, reso);
   getline(read, cost);
   getline(read, pric);
   getline(read, quan);
   getline(read, readSpace); // store space as well
                        
   }// end while
   
   // reset counter
   counter = 0;   
   
   // reposition to beginning and close files
   read.clear();
   read.seekg(0);
   read.close();
   write.close();
   
   // open files again
   read.open("temp.txt");
   write.open("Printers.txt",ios::out);
      
   write << ""; // clear original file
   
   // read from temp file
   getline(read, num);
   getline(read, name);
   getline(read, manu);
   getline(read, type);
   getline(read, reso);
   getline(read, cost);
   getline(read, pric);
   getline(read, quan);
   getline(read, readSpace); // store space as well
   
   
   while(!read.fail())
   {   
       // write back to the original file the amended information
       write << num << endl // insert new item numbering
             << name << endl
             << manu << endl
             << type << endl
             << reso << endl
             << cost << endl
             << pric << endl
             << quan << endl
             << endl; // inserts a space between records
                      
             // read another record                       
             getline(read, num);
             getline(read, name);
             getline(read, manu);
             getline(read, type);
             getline(read, reso);
             getline(read, cost);
             getline(read, pric);
             getline(read, quan);
             getline(read, readSpace); // store space as well
   }// end while
   
   // reposition to beginning of temp file and close files
   read.clear();
   read.seekg(0);
   read.close();
   write.close();
   
   // open temp and clear contents
   write.open("temp.txt", ios::out);
   write << ""; 
   write.close();
   
         
}

This is really too much code for what it does! There must be a more efficient way?