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Held needed with regards to reading from a file

2 New Member
Hi All,

New member here with a bit of problem. I have read the FAQ's and searched text books but still cannot solve the problem that I have.

As part of a course I am doing at University I had to write a program in C++ that would allow the user to enter student information (matriculation number, name, status and mark), which was then stored in an array. They could then search it or list it. Everything was woking (and still is) up to here. We then had to add in two functions that would allow the user to save the array to disk and/or load it back from disk.

I added two functions (included below) int loadFile() and int saveFile() which would load a file from disk or save a file to disk. I can save the file to disk and when looking at the txt file everything appears to be OK. Here is a sample text file that it saves.

Expand|Select|Wrap|Line Numbers
  1. A001
  2. George Price
  3. P
  4. 99
  5. A002
  6. Fred Bloggs
  7. P
  8. 98
  9. A003
  10. Joe Public
  11. F
  12. 40
  13.  
The problem appears to be when I am trying to bring the text file back into the array. It appears that I am only reading the first name of the studentsList[].name
when it should be reading the full line. If I only enter the names as a single name everything works great. Therefore I think the error is in my loadaFile function.

I have tried both

Expand|Select|Wrap|Line Numbers
  1. infile >> studentsList[currentSize].name;
  2.  
  3. // and 
  4.  
  5. getline(infile, studentsList[currentSize].name);
but neither of them will pull in both parts of the name, although the infile option works great for single names.

Here is the code that I think has the problem.
Expand|Select|Wrap|Line Numbers
  1. //declare structure type 
  2.  
  3. struct studentRecord{
  4.     string matricNumber;
  5.     string name;
  6.     string status;
  7.     int mark;
  8.     };
  9.  
  10.     const int listSize = 30;                //number of records in array
  11.     int currentSize;
  12.  
  13. //declare a list of records
  14. studentRecord studentsList[listSize];        //global array of records
  15.  
  16. //function prototypes
  17. void addStudentRecords();
  18. void displayAllRecords();
  19. void displayMenu(int &option);
  20. void searchRecordMenu();
  21. void searchByMatric();
  22. void searchByName();
  23. void displaySearchMenu(int &choice);
  24. int saveFile();
  25. int loadFile();
  26.  
......

Expand|Select|Wrap|Line Numbers
  1. int loadFile()
  2. {
  3.     currentSize = 0;
  4.  
  5.     //open an input file
  6.  
  7.     ifstream infile("c:\\UniWorkspace\\students.txt", ios::in);
  8.  
  9.     // check if file is opened
  10.     if(!infile)                //return true if file is not opened
  11.     {
  12.         cout << "\nFailed to open file !!\n";
  13.         cout << "Press any key to proceed\n";
  14.         cin.get();
  15.         return 1;            //indicate program failed
  16.     }
  17.  
  18.     while(!infile.eof())        //eof() End Of File function. Returns false if the end of file reached
  19.     {
  20.  
  21.             infile >> studentsList[currentSize].matricNumber;
  22.             infile >> studentsList[currentSize].name;
  23. //            getline(infile, studentsList[currentSize].name);    //tried alternate getline as name would normally have space in middle. This didn't work either!!
  24.             infile >> studentsList[currentSize].status;
  25.             infile >> studentsList[currentSize].mark;
  26.  
  27. // The following lines were added to allow me to view the data coming in
  28.  
  29.             cout << "Loop count at " << currentSize << endl;        
  30.             cout << studentsList[currentSize].matricNumber << " "    
  31.                 << studentsList[currentSize].name << " "            
  32.                 << studentsList[currentSize].status << " "            
  33.                 << studentsList[currentSize].mark << endl;        
  34.  
  35. // End of extra line - to be removed once working    
  36.  
  37.             currentSize += 1;            //increment record index
  38.             cout << "\nPress any character to proceed\n";
  39.             cin.get();
  40.     }
  41.  
  42.     infile.close();                //close file
  43.     currentSize = currentSize - 1;
  44.     cout << "\nCurrentSize = " << currentSize << endl;
  45.     cout << "Press any character to proceed\n";
  46.     cin.get();
  47.     return 0;
  48.  
  49. }
  50.  
  51.  
  52. int saveFile()
  53. {
  54.     int i;
  55.  
  56.     //create and open an output stream called students.txt
  57.     ofstream outfile("c:\\UniWorkspace\\students.txt", ios::out);
  58.  
  59.     //check if file is opened
  60.     if(!outfile)                //return true if file is not opened
  61.         {
  62.             cout << "\nFailed to open file!!\n";
  63.             cout << "\nPress any key to proceed ";
  64.             cin.get();
  65.             return 1;
  66.         }
  67.  
  68.     for(i=0; i<currentSize; i++)
  69.         {
  70.             outfile << studentsList[i].matricNumber << endl;
  71.             outfile << studentsList[i].name << endl;
  72.             outfile << studentsList[i].status << endl;
  73.             outfile << studentsList[i].mark << endl;
  74.         }
  75.  
  76.     outfile.close();        //closes file
  77.  
  78.     cout << "\nFile closed" << endl;
  79.     cin.get();
  80.  
  81.     return 0;
  82. }

Thanks in advance..
Geo
Jan 5 '07 #1
2 1744
Ganon11
3,652 Recognized Expert Specialist
If you are using getline(infile, stringVariable) , it may be retrieving the data from the previous line, which would give it something like A001 for the name. You would have to use an infile.ignore() function call before your getline call. I'm not sure how this would work, though, once you started looping. It might be easier if you declare two string variables - first and last - use infile >> to retrieve these strings, and then concatenate them (with a space between them) to form your overall name variable.
Jan 5 '07 #2
GeoUK
2 New Member
Thanks for the fast responce. I have amended the code in the loadFIle() function as follows and it now appears to work.

Expand|Select|Wrap|Line Numbers
  1. infile >> studentsList[currentSize].matricNumber;
  2. infile.get();                                                   //added
  3. getline(infile, studentsList[currentSize].name);    //now gets the line as expected
  4. infile >> studentsList[currentSize].status;
  5. infile >> studentsList[currentSize].mark;
  6.  

Thanks again,

Geo
Jan 5 '07 #3

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