从文件 c++ 创建一个字符串向量

Question

我正在尝试从 a.txt 文件中输入三条信息。

第一列是课程标记。 第二列是课程代码。 第三列是课程名称。

我想将这些存储为 3 个字符串向量。

在这里使用 stringstream 会是一个不错的选择吗？ 也许是迭代器？

.txt 文件就像

65.6 10071   Mathematics 1
66.7 10101   Dynamics
60.0 10121   Quantum Physics and Relativity
66.9 10191   Introduction to Astrophysics and Cosmology
...  ...    ...

到目前为止我的代码是

#include<iostream>
#include<iomanip>
#include<fstream>
#include<cmath>
#include<algorithm>
#include<string>
#include<iterator>
#include<sstream>
#include<vector>

//Main Function
int main()
{

  //Define variables
  std::string course_mark, course_code, course_name;
  std::vector<std::string> course_mark_vector;
  std::vector<std::string> course_code_vector;
  std::vector<std::string> course_name_vector;

  std::string data_file[100];

  // Ask user to enter filename
  std::cout<<"Enter data filename: ";
  std::cin>>data_file;

  int i{0};

  // Open file and check if successful
  std::fstream course_stream(data_file);

  if(course_stream.is_open()) {
        while (!course_stream.eof()) //while the end of file is NOT reached
        {
            //I have 2
            getline(course_stream, course_mark, ' ');
            course_mark_vector.push_back(course_mark);

            getline(course_stream, course_code, ' ');
            course_code_vector.push_back(course_code);

            getline(course_stream, course_name, '\n');
            course_name_vector.push_back(course_name);
            
            i += 1; //increment number of lines
        }
        course_stream.close(); //closing the file
        std::cout << "Number of entries: " << i-1 << std::endl;
    }

  else{
        std::cout << "Unable to open file. Please run again" << std::endl;
        return 1;
  }

任何帮助将不胜感激

Answer 1

在这里使用 stringstream 会是一个不错的选择吗？

是的。

也许是迭代器？

在这种情况下不需要迭代器。

尝试这个：

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <iomanip>

//Main Function
int main()
{
    //Define variables
    std::string course_mark, course_code, course_name, data_file, line;
    std::vector<std::string> course_mark_vector, course_code_vector, course_name_vector;
    int i = 0;

    // Ask user to enter filename
    std::cout << "Enter data filename: ";
    std::cin >> data_file;

    // Open file and check if successful
    std::ifstream course_stream(data_file);

    if (!course_stream.is_open())
    {
        std::cout << "Unable to open file. Please run again" << std::endl;
        return 1;
    }

    while (std::getline(course_stream, line)) //while the end of file is NOT reached
    {
        std::istringstream iss(line);

        iss >> course_mark;
        course_mark_vector.push_back(course_mark);

        iss >> course_code;
        course_code_vector.push_back(course_code);

        std::getline(iss >> std::ws, course_name);
        course_name_vector.push_back(course_name);
            
        ++i; //increment number of lines
    }

    course_stream.close(); //closing the file
    std::cout << "Number of entries: " << i << std::endl;

    return 0;
}

演示