使用ifstream将文件（包含int，string）读取到对矢量

Question

我正在尝试将文本文件读成对的向量。文本文件包含以下内容：第一行说明有多少字符串。第二行是一个int，告诉第一个字符串中有多少个字符。然后，第三行包含字符串本身。之后，接下来是“模式”（再次使用int有多少个字符，然后是字符串本身）。例如：

• 2
• 3
• ABC
• 4
• CDEF

我的想法是，分别阅读第一行（工作正常）。然后为每个int和string创建对。第二部分，不知何故，不起作用，所以如果有人能帮我找到错误，我真的很感激。

所以这是我的代码：

#include <iostream>
#include <stdlib.h>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <utility>

using namespace std;

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

if (argv[1]) 
{some code here...}

// arg[2] is formatted in some manner of the example above

if (argv[2])
{

//Declare Variables:
    string buffer;
    string temporary;
    vector <pair <int, string> >  patVec;
    pair <int, string> patPair;

// Ifstream first txt File = (argv[2]

        ifstream ifile2(argv[2]);

// Get first line and store in variable number of Patterns --> This works fine

        getline(ifile2, temporary);
        int numberOfPatterns = atoi(temporary.c_str());
// Process rest of file

       int i;
       for (patVec[i=0]; i <= numberOfPatterns - 1; i++)
        {
         getline(ifile2, buffer);

         stringstream strs(buffer);

 // Fill up the Vector with pairs
            strs >> patPair.first;
            strs >> patPair.second;

            patVec.push_back(patPair);
        }
    }
 }

所以这是相关部分的更正版本，现在有效：感谢提示;）

    //Declare Variables
    string buffer;
    string temporary;
    vector <pair <int, string> >  patVec;
    pair <int, string> patPair;
    int plength;
    string pCharacters;

    // Get first line and store in variable number of Patterns

    getline(ifile2, temporary);

    int numberOfPatterns = atoi(temporary.c_str());

    cout << "The number of Patterns is " << numberOfPatterns << endl;


    // Process rest of file

    for (int i=0; i <= numberOfPatterns - 1; i++)
    {

       // stringstream strs(buffer);

        // Fill up the Vector with pairs
        getline(ifile2, buffer);
        stringstream int_reader(buffer);
        int_reader >> plength;

        getline(ifile2, buffer);
        stringstream str_reader(buffer);
        str_reader >> pCharacters;


        patPair = make_pair (plength, pCharacters);

        patVec.push_back(patPair);

        cout << "length of pattern " << i << " is " << plength << endl;
        cout << " characters are: " << pCharacters << endl;

    }

        ifile2.close();

    }

Answer 1

这是一个更正的程序。它仍然存在一些问题，例如：

1. 变量的预先声明。
2. 这对没有typedef。

但它看起来效果很好。

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

int main(int argc, char * argv[])
{
    //Declare Variables:


    std::string buffer;
    std::string temporary;
    std::vector <std::pair <int, std::string> >  patVec;
    std::pair <int, std::string> patPair;

    // Ifstream first txt File = (argv[2]

    std::ifstream ifile2((const char *)(argv[2]));

    // Get first line and store in variable number of Patterns --> This works fine

    getline(ifile2, temporary);
    int numberOfPatterns = atoi(temporary.c_str());
    // Process rest of file

    for (int i = 0 ; i <= numberOfPatterns - 1; i++)
    {
        getline(ifile2, buffer);

        std::stringstream int_reader(buffer);

        // Fill up the Vector with pairs
        int_reader >> patPair.first;

        getline(ifile2, buffer);
        std::stringstream str_reader(buffer);
        str_reader >> patPair.second;

        patVec.push_back(patPair);
    }

    return 0;
}