Question

If I open a new file for input, and I call input >> listSize; outside of a while loop and then continue calling input >> anothervariable will it automatically progress through the file or will it read the first line again?

Example:

input >> listSize;
BaseStudent* studentlist = new BaseStudent[listSize.atoi()];
while (!input.eof())
{
         input >> anothervariable; // I want this to start on the second line, not the first

}

The input file looks like this and we can code to the pattern (ignore the extra blank lines):

12

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

Nixon, Richard

English 35 99 70 70

Lincoln, Abraham

History 59 71 75

Clinton, William

Math 43 55 25 76 50 58 65

Duck, Donald

English 34 100 65 65

Duck, Daffy

History 55 70 70

Bush, George

Math 44 54 29 75 50 55 60

Answer 1

Others have already pointed out that the answer to your question is “yes”, so I won’t worry about that part.

As for the rest, I think I’d write it a bit differently. Your file obviously represents structured data, and I’d write the code to reflect that fact reasonably directly. I’d start by defining a structure reflecting the data in the file:

struct test_scores {   // maybe not tests. Change if appropriate
    std::string student;
    std::string course;
    std::vector<int>
};

Then, I’d write a function to read one of those items from the file:

std::istream &operator>>(std::istream &is, test_scores &ts) { 
    // for the moment assuming there are no blank lines in the file.
    std::getline(is, ts.student);
    std::string temp;
    std::istringstream buffer(temp);
    buffer >> ts.course;
    int score;
    while (buffer>>score)
        ts.scores.push_back(score);
    return is;
}

In C++, however, it’s really easier to just read whatever amount of data is there, than to prefix the data with the count. Given that count is present, the easiest thing to do is probably to just read and ignore it:

std::string ignore;
std::getline(infile, ignore);

Then we can read the real data pretty easily:

std::vector<test_scores> student_scores;
test_scores tmp;

while (infile >> tmp)
    student_scores.push_back(tmp);

…or, we can use C++’s handy-dandy istream_iterators to simplify the code even more:

std::vector<test_scores> student_scores((std::istream_iterator<test_scores>(infile)),
                                         std::istream_iterator<test_scores>());

That’s it — it defines the vector and initializes it from the input file, all in one (fairly) simple operation.