操纵输入文件流 [英] Manipulate Input File Stream

问题描述

我有一个数据文本文件，其中包含以下内容

I have a data text file which contains this

Map2D, [3, 2]
Dot3D, [25, -69, -33], [-2, -41, 58]
Map3D, [6, 9, -50]
Map2D, [3, 2]
Dot3D, [7, -12, 3], [9, 13, 68]
Map3D, [6, 9, 5]
Map2D, [3, 2]
Dot3D, [70, -120, -3], [-29, 1, 268]
Dot3D, [7, 12, 3], [-9, 13, 68]
Map3D, [1, 3, 8]
Dot2D, [5, 7], [3, 8]

基本上是文本文件的第一个数据是我获得4个班级的班级名称

Basically the text file first data is the class name which i got 4 class

Map2D
Map3D
Dot2D
Dot3D

我正在尝试编写自己的文件操纵器，以便我的程序可以提取上面的数据并重载提取对于这4个类别中的每个类别，然后将其存储到相关对象中。

I was trying to write my own file manipulator so that my program can extract the data above and overload the extraction operator >> for each of the 4 class and then storing it into relevant object.

我当时正在考虑使用vector，map，set或list进行存储。

I was thinking of using vector, map, set or list to store . but for this how do i achieve what i want to do such as store into relevant object of the class.

我尝试使用谷歌搜索方法来创建自己的文件操纵器，但是如果有人可以给我看一些示例代码，并且我可以在测试文件中编译并执行它，然后自己观察输出，那将是很好的。我想使用iomanip对>>运算符进行重载

I tried googling around on how to create my own file manipulator, but will be good if someone could show me some sample code and i can compile and execute it maybe in a test file then observe the output myself. I would like to use iomanip to do a overload on the >> operator

我必须使用操纵器，因为我需要创建类似

I have to use manipulator because i need create something like

我需要做

cout << "Input File Name";
cin >> readFile;

并执行所有数据读取和处理；创建对象

and perform all the data reading & object creation

对于造成的所有麻烦，我深表歉意。然后它将逐行读取记录，然后创建类以及其中的数据。

I am sorry for all the trouble caused. then it will read the records line by line, then create the class and also the data in it.

感谢您的所有帮助！

推荐答案

这是 std :: cin 的示例。 fstream 应该可以正常工作。解析您的输入确实很讨厌。是否可以从输入中删除方括号（ [ amd]）？

This is an example with std::cin. It should work just fine with a fstream. parsing your input is really nasty. Is it possible to remove the brackets("[" amd "]") from the input?

#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <algorithm>
#include <c>

class Map2D {
    std::vector<int> values;
public:
    friend std::istream& operator>>(std::istream& in, Map2D m) {
        std::string i;
        in >> i;
        std::stringstream ss(i);
        std::getline(ss, i, '[');
        std::getline(ss, i, ',');
        ss >> i;
        std::cout << i << std::endl;
        in >> i;
        ss.str("");
        ss << i;
        i = i.substr(0, i.size()-1);
        ss >> i;
        std::cout << i << std::endl;;
    }
};

int main() {
    std::string type, file_name;
    std::cout << "Input File Name";
    std::cin >> file_name;
    std::fstream file(file_name.c_str());
    Map2D m;
    while (std::getline(std::cin, type, ',')) {
        if(type.find("Map2D") != std::string::npos) {
            file >> m;
        }
    }
}

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