ifstream irregular pattern

Question

I am having trouble pinpointing where exactly my file input is going wrong. Here is the code:

  char tempFirst[20], tempLast[20], tempCourse[7];
  char c;          // For peeking


  // Find out how many students are in the file
  inFile >> numStudents;

  for (int i = 0; i < numStudents; i++)
    {
      // Get last name from file
      inFile.getline(tempLast, 20, ',');

      // Gets rid of any spaces inbetween last and first
      while (isspace(inFile.peek()))
        c = inFile.get();
      // Get first name from file
      inFile.getline(tempFirst, 20, '\n');

      // New line, get course
      inFile >> tempCourse;

      // PRINT
      cout << tempFirst << "\n" << tempLast << "\n"
             << tempCourse << "\n";

      list[i]->SetGrades(inFile);
    }

SetGrade leads to one of these three inherited functions:

void EnglishStudent::SetGrades(ifstream& inFile)
{
  inFile >> attendance >> project >> midterm >> final;
  cout << attendance << " " << project << " " << midterm << " " << final << "\n\n";
}

void HistoryStudent::SetGrades(ifstream& inFile)
{
  inFile >> paper >> midterm >> final;
  cout << paper << " " << midterm << " " << final << "\n\n";
}

void MathStudent::SetGrades(ifstream& inFile)
{
  inFile >> quiz1 >> quiz2 >> quiz3 >> quiz4 >> quiz5
         >> test1 >> test2 >> final;
  cout << quiz1 << " "<< quiz2 << " " << quiz3 << " " << quiz4 << " " << quiz5
       << " " << test1 << " " << test2 << " " << final << "\n\n";
}

Here is the file I am loading the information in from:

6
Bunny, Bugs
Math 90 86 80 95 100 99 96 93
Schmuckatelli, Joe
History 88 75 90
Dipwart, Marvin
English 95 76 72 88
Crack Corn, Jimmy
Math 44 58 23 76 50 59 77 68
Kirk, James T.
English 40 100 68 88
Lewinsky, Monica
History 60 72 78

Then here is the output:

Bugs

Bunny
Math
90 86 80 95 100 99 96 93

Joe

History
88 75 90

Marvin

English
95 76 72 88

Jimmy

Crack Corn
Math
44 58 23 76 50 59 77 68

James T.

English
40 100 68 88

Monica

History
60 72 78

I am missing most last names and for the first student, firstname has an endline included. How would I go about fixing this?

Answer 1

It's not that the first name has a newline at the end, it's that the last name has a newline at the beginning. When the ints are read from the input, any whitespace encountered that marks the end of the int is left in the input stream.

To fix this, either remove whitespace before reading the last name, in the SetGrades methods or at the end of the loop. The latter two will also require removing whitespace after reading numStudents. The easiest way of removing whitespace is with the ws stream manipulator. All it takes is:

inFile >> ws;

You can also replace your peeking loop with this.

Replace the character arrays with strings for a more genuine C++ experience. This also necessitates replacing ifstream::getline with the getline free function. As a bonus, your code will work for names longer than 19 characters.

    std::string tempFirst, tempLast, tempCourse;

    ...
    for (int i=0; i < numStudents; ++i) {
        inFile >> std::ws;
        getline(inFile, last, ',');

        inFile >> std::ws;
        getline(inFile, first, '\n');
        ...

Answer 2

skip the rest of current line before you move to the next line

   inFile >> numStudents;
    std::string line;
    std::getline(inFile, line);//read the rest of the first line, you should do this before you start to read next line
    for (int i = 0; i < numStudents; i++)
    {
        std::getline(inFile, line); //line contains first name and last name
        size_t pos = line.find(",");
        std::cout << line.substr(0, pos) << std::endl //first name
            << line.substr(pos + 2) << std::endl; //last name,skip ", "
        std::getline(inFile, line); // course name and grades
        //you could split the course name and grades now with line
        std::cout << line << std::endl;
    }