将并行数组与txt文件分开

debugcn 发表于 Dev

詹姆森

我是一个非常新手的程序员，我正在尝试制作一个程序，以读取一个txt文件，其中包含5个学生的姓名（仅名字）以及每个学生的4个考试成绩。我正在尝试将名称读入一个名为“ students”的数组中，然后将分数读入4个名为test1，test2，test3，test4的单独数组中，然后从监视器显示它。该文件如下所示：

史蒂夫78 65 82 73

肖恩87 90 79 82

安妮92 90 89 96

卡罗尔72 65 65 60

凯西34 50 45 20

我很难分解数组并组织它们。有人能帮我吗？请记住，我是新手，所以我对编程不了解很多。

到目前为止，这是我的代码：

#include <cstdlib>
#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
#include <ctime>
#define over2 "\t\t"
#define over3 "\t\t\t"
#define over4 "\t\t\t\t"
#define down5 "\n\n\n\n\n"


using namespace std;



int main(int argc, char *argv[])
{

    
    ifstream inputFile;
    
    
    //Constant for max string size
    const int SIZE = 5;
     

    //Constant for the scores
    string names[SIZE], fileName, line, test1[SIZE], test2[SIZE], test3[SIZE], test4[SIZE];


    //input section, user enters their file name
    cout << down5 << down5 << over2 << "Please enter your file name: ";
    cin >> fileName;
    system("CLS");
    

    

    //open the file containing the responses
    inputFile.open(fileName.c_str());
     cout << endl;

    //kicks you out if file isn't found
    if (inputFile)
    {
        for(int i = 0; i < SIZE; i++)
        {  
           getline(inputFile, line);
            names[i] = line;
            getline(inputFile, line);
            test1[i] = line;
            getline(inputFile, line);
            test2[i] = line;
            getline(inputFile, line);
            test3[i] = line;
            getline(inputFile, line);
            test4[i] = line;
        }   
            inputFile.close();  
    }
    cout << down5 << over3 << "Student\tTest1\tTest2\tTest3\tTest4\n";
    cout << over3 << "-------\t-----\t-----\t-----\t-----\n";   
    for(int i = 0; i < SIZE; i++)
    {
        cout << over3 << names[i] << endl;
        cout << over3 << test1[i] << endl;
        cout << over3 << test2[i] << endl;
        cout << over3 << test3[i] << endl;
        cout << over3 << test4[i] << endl;
        
    }
    return 0;
}

GoBusto

让我们看一下您要读取的文件的结构：

Steve 78 65 82 73
Shawn 87 90 79 82
Annie 92 90 89 96
Carol 72 65 65 60
Kathy 34 50 45 20

数据格式可以描述如下：

每行代表一个“记录”。
每个“记录”包含多个列。
列由空格分隔。

您当前正在使用getline()每列：

for(int i = 0; i < SIZE; i++)
{  
  getline(inputFile, line);
  names[i] = line;
  getline(inputFile, line);
  test1[i] = line;
  getline(inputFile, line);
  test2[i] = line;
  getline(inputFile, line);
  test3[i] = line;
  getline(inputFile, line);
  test4[i] = line;
}

...而您实际上想为每条记录读一行并将其拆分：

for (int i = 0; i < SIZE; i++)
{
  string line;
  size_t start = 0;
  // For each line, attempt to read 5 columns:
  getline(inputFile, line);
  names[i] = get_column(line, start);
  test1[i] = get_column(line, start);
  test2[i] = get_column(line, start);
  test3[i] = get_column(line, start);
  test4[i] = get_column(line, start);
}

这是原始代码的修改后的版本，该代码如上所述将每一行拆分：

#include <cctype>
#include <fstream>
#include <iostream>
#include <string>

using namespace std;

static string get_column(string line, size_t &pos)
{
  size_t len = 0;
  // Skip any leading whitespace characters.
  while (isspace(line.c_str()[pos])) { ++pos; }
  // Count the number of non-whitespace characters that follow.
  while (!isspace(line.c_str()[pos+len]) && line.c_str()[pos+len]) { ++len; }
  // Extract those characters as a new string.
  string result = line.substr(pos, len);
  // Update the "start" position (for the next time this function is called).
  pos += len;
  // Return the string.
  return result;
}

int main()
{

  const int SIZE = 5;
  string names[SIZE], test1[SIZE], test2[SIZE], test3[SIZE], test4[SIZE];

  // Ask the user to enter a file name.
  cout << "Please enter your file name: ";
  string fileName;
  cin >> fileName;

  // Open the file and read the data.
  ifstream inputFile(fileName.c_str());
  if (!inputFile.is_open()) { return 0; }

  for (int i = 0; i < SIZE; i++)
  {
    string line;
    size_t start = 0;
    // For each line, attempt to read 5 columns:
    getline(inputFile, line);
    names[i] = get_column(line, start);
    test1[i] = get_column(line, start);
    test2[i] = get_column(line, start);
    test3[i] = get_column(line, start);
    test4[i] = get_column(line, start);
  }

  inputFile.close();

  // Display the data.
  cout << "Student\tTest1\tTest2\tTest3\tTest4" << endl;
  cout << "-------\t-----\t-----\t-----\t-----" << endl;

  for(int i = 0; i < SIZE; i++)
  {
    cout << names[i] << "\t";
    cout << test1[i] << "\t";
    cout << test2[i] << "\t";
    cout << test3[i] << "\t";
    cout << test4[i] << endl;
  }

}

运行该程序将产生以下输出：

Please enter your file name: textfile.txt
Student Test1 Test2 Test3 Test4
------- ----- ----- ----- -----
Steve   78    65    82    73
Shawn   87    90    79    82
Annie   92    90    89    96
Carol   72    65    65    60
Kathy   34    50    45    20

请注意，该get_column()函数处理多个空格或太短的行，因此该文件：

Steve 78     65 82 73
Shawn   87 90 
Annie 92 90 89 96
Carol 72 
Kathy 34 50   45 20

...产生以下输出：

Please enter your file name: textfile.txt
Student Test1 Test2 Test3 Test4
------- ----- ----- ----- -----
Steve   78    65    82    73
Shawn   87    90
Annie   92    90    89    96
Carol   72
Kathy   34    50    45    20

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