Question

The code below should do the following:
List all students taking a module, showing their marks and the average overall mark

It does what it suppose to do however, the problem is that the output doesn’t show the marks and instead show the enrollment number

My mark text file

11  IS1S01  25 
11  SE1S02  50 
11  SE2S04  75 
12  CS3S08  15 
12  CS1S03  20
13  CS1S03  25 
14  CS1S03  50 

Where it should display the following:

11   IS1S01   25

Average = 25

When it run the program, it display the following instead:

11   IS1S01    11

Average = 1.1

It not reading in marks for some reason. I can’t seem to find why it doing it

void studentmark()
    {
        float Marks;
        float Average;
        float EnrolmentNo;
        std::string module;

    // Display message asking for the user input
    std::cout << "\nList all students taking a module, showing their marks." << std::endl;

    // List of options
    std::cout << "\nInformation Resource Engineering:   IS1S01" << std::endl;
    std::cout << "C++ Programming:          SE2S552" << std::endl;
    std::cout << "Data Structures and Algorithms:       CS2S504 " << std::endl;
    std::cout << "AI for Game Developers:           CS3S08" << std::endl;
    std::cout << "Cognitive Science:            MS3S28" << std::endl;
    std::cout << "Game Modification:            CS1S03" << std::endl;
    std::cout << "Building:             BE1S01" << std::endl;
    std::cout << "Plumbing:             BE2S01" << std::endl;
    std::cout << "Coaching:             SS1S02" << std::endl;
    std::cout << "Psychology:               CC1S04" << std::endl;
    std::cout << "Mental Health Care:           SS2S01" << std::endl;
    std::cout << "Missing Module:               SE1S02" << std::endl;

    std::cout << "\nEnter your preferred module:";

    // Read in from the user input
    std::cin >> module;

    // Read from text file and Display list of marks by each student in a particular module

    std::ifstream infile;               // enable to open, read in and close a text file

    infile.open("Mark.txt");            // open a text file called Mark

    if (!infile)                 
    {
        std::cout << "List is empty" << std::endl;      // if the file is empty it output the message
    } 
    else 
    {
        std::cout << "\nList of marks for students: " << std::endl;

        std::string moduleCode;

        while (infile) 
        {
            infile >> EnrolmentNo >> moduleCode >> Marks;
            if (infile) 
            { 
                // strings read correctly
                if (moduleCode == module) 
                {
                    //std::cout << " ";
                    std::cout << "\nEnrolmentNo" << "       " << "Module Code" << " " << "Marks" << std::endl;

                    int sum=0;
                    for(int i=0;i<10;i++)
                    {
                        if(infile>>Marks)
                        {
                            sum+=Marks;
                        }
                    }

                    std::cout << EnrolmentNo << "           " << moduleCode << "        " << Marks << std::endl;

                    float Average = (double)sum/10.0;

                    std::cout << "\nThe average mark of the module: " << Average << std::endl;
                }
            }
        }
    }

    infile.close();         // close the text file  
    system ("PAUSE");
}

Answer 1

The flow of your reading code is weird. You start by reading EnrolmentNo, moduleCode and Marks. Then, if it’s the module you’re interested in, you start reading Marks from the same spot in the file, until a non-integer is found.

With the example file you gave (and assuming user enters IS1S01 as module), the read proceeds like this:

1. EnrolmentNo gets the first 11
2. moduleCode gets IS1S01
3. Marks gets 25

Then the inner loop kicks in and:

1. Marks gets the next 11 (from line 2)
2. loop terminates, because Marks tries to read “SE1S02”, and fails

Given the file you’ve shown, you should probably get rid of the inner for loop and do the sum/averaging in the outer loop.