C++：讀取分隔文件並存儲在結構中

Question

我是編程新手，所以我可以使用你的幫助與我的代碼。我想讀取一個數據格式像這樣一個現有的文件：我張貼了我所有的代碼

2012-09-22|microsoft|0|102.36|100 
2012-09-22|apple|0|203.12|100 
2012-10-05|ibm|0|141.96|100 
2012-10-05|boeing|0|123.65|100 
2012-11-03|sears|0|23.36|100 
2012-11-29|toyota|0|78.45|100 

，但相關功能是無效loadData（交易allTransaction）;功能。我從這裏找到的多個示例中共同破解了這些代碼，但它並不適合我。我正在嘗試讀取數據，然後填充allTransaction結構的變量。然後我想將該結構推送到數據向量。我想循環每一行，直到到達文件末尾。它看起來像我沒有得到填充結構的值。請幫忙！

我一直在做這個編程2個月現在爲學校，所以請保持您的響應noob級別。

感謝

#define _CRT_SECURE_NO_DEPRECATE // Declaration to use deprecated code in Visual Studio. 

#include <iostream> // Include the iostream standard file. 
#include <string> // Include the string library. 
#include <fstream> // Include to manipulate files. 
#include <vector> // Include to use vectors. 
#include <sstream> // Include to use stringstream. 
#include <ctime> // Include to calculate time. 

using namespace std; 

// Create transactions structure 
struct transaction 
{ 
    /*int user = 0;*/ 
    string date = ""; 
    string stock = ""; 
    bool sale = 0; 
    double price = 0.0; 
    int shares = 0; 
}; 

// Create vector 
vector <transaction> data; 

// Function declarations 
void loadData(transaction allTransaction); 
void buyShares(transaction allTransaction); 
void sellShares(transaction allTransaction); 
void storeData(transaction allTransaction); 

int main() 
{ 

    // Declare variables 
    transaction allTransaction; // Declaring a structure. 

    loadData(allTransaction); 

    cout << "Date: " << allTransaction.date << 
     "Name: " << allTransaction.stock << 
     "Sale?: " << allTransaction.sale << 
     "Price: " << allTransaction.price << 
     "Shares: " << allTransaction.shares; 

    //Pause program 
    cout << "Press Enter To Continue..." << endl; 
    cin.ignore(); 
    cin.get(); 
    return 0; 

} 

// Load text file function 
void loadData(transaction allTransaction) 
{ 

    string line; 
    ifstream myfile("data.txt"); 
    if (myfile.is_open()) 
    { 
     while (getline(myfile, line)) 
     { 
      istringstream f(line); 
      string s; 
      while (getline(f, s, '|')) { 
       myfile >> allTransaction.date >> 
        allTransaction.stock >> 
        allTransaction.sale >> 
        allTransaction.price >> 
        allTransaction.shares; 
       data.push_back(allTransaction); 
      } 
      myfile.close(); 
     } 
    } 
    else std::cout << "Unable to open file"; 

} 

// Buy stock function 
void buyShares(transaction allTransaction) 
{ 
    allTransaction.sale = 0; // Set sale boolean to 0, indicating a buy. 
    storeData(allTransaction); // Call storeData function to store the data. 
} 

// Sell stock function 
void sellShares(transaction allTransaction) 
{ 
    allTransaction.sale = 1; // Set sale boolean to 1, indicating a sell. 

    // Need function to check shares on hand. 

    storeData(allTransaction); // Call storeData function to store the data. 
} 

void storeData(transaction allTransaction) 
{ 
    ofstream myfile; 
    myfile.open("data.txt", ios::out | ios::app); 
    myfile << allTransaction.date << "|" << allTransaction.stock << "|" << allTransaction.sale << "|" << 
     allTransaction.price << "|" << allTransaction.shares << '\n'; 
    myfile.close(); 

    data.push_back(allTransaction); 
} 

Answer 1

一件事浮現在我的眼裏是這樣的循環：

while (getline(f, s, '|')) { 
    myfile >> allTransaction.date >> 
     allTransaction.stock >> 
     allTransaction.sale >> 
     allTransaction.price >> 
     allTransaction.shares; 
    data.push_back(allTransaction); 
} 

首先，你從istingstream讀f控制分隔符 '|' （這是一件好事），但在while循環體內，你再次從文件中讀取（這不是你想要的）。你可以做這樣的事情。

std::vector<std::string> v; 
    while (getline(f, s, '|')) { 
     v.push_back(s); 
    } 
    if(v.size()!=5) { 
     std::cerr << "expected 5 values" << std::endl; 
     return false; // or throw an exception etc... 
    } 
// At this point you have a vector with the strings 
// delimited by '|' ready for processing 
// into your allTransaction class