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下面的代码应该执行以下操作：列出所有参加模块的学生，显示他们的分数和平均总分

它做了它应该做的事情，但问题是输出不显示分数而是显示注册号

我的标记文本文件

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

它应该在哪里显示以下内容：

11   IS1S01   25

Average = 25

当它运行程序时，它会显示以下内容：

11   IS1S01    11

Average = 1.1

由于某种原因，它没有读取标记。我似乎无法找到它为什么这样做

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");
}
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1 回答 1

2

您阅读代码的流程很奇怪。您首先阅读EnrolmentNo,moduleCode和Marks。然后，如果它是您感兴趣的模块，Marks 则从文件中的同一位置开始读取，直到找到一个非整数。

使用您提供的示例文件（并假设用户输入IS1S01as module），读取过程如下：

  1. EnrolmentNo获得第一个 11
  2. moduleCode获得 IS1S01
  3. Marks得到 25

然后内部循环启动并且：

  1. Marks获取下一个 11（从第 2 行开始）
  2. 循环终止，因为Marks尝试读取“SE1S02”，但失败

鉴于您显示的文件，您可能应该摆脱内for循环并在外循环中进行求和/平均。

于 2012-12-13T13:30:17.300 回答