使用Windows线程的C++ File Writer-Reader应用程序

在本文中，我们将创建一个简单的Writer-Reader应用程序，该应用程序使用两个线程，一个用于写入文件，另一个用于从文件读取。在这里，我们将讨论在C / C++中使用Win32线程的方法。可以使用CreateThread()方法创建Windows线程。

方法：

1. 创建用于从文件读取数据的线程函数

   // Thread function used to Read data from the file
   DWORD WINAPI ReadFromAFile(PVOID lpParam)
   {
       // Create a buffer
       char buffer[1024] = { 0 };
     
       // Creating ifstream object
       ifstream fileReader;
     
       // Opening the file in read mode
       fileReader.open("sample.txt");
     
       // Reading the data into the buffer
       cout << "Reading data from the file:";
     
       // Printing the data onto the console
       cout << buffer << endl;
     
       // Closing the opened file
       fileReader.close();
     
       return 1;
   }
   

2. 创建用于将数据写入文件的线程函数

   // Thread function used to Write data into the file
   DWORD WINAPI WriteIntoAFile(PVOID lpParam)
   {
       // Create a buffer
       char buffer[1024] = { 0 };
     
       // Creating ofstream object
       ofstream fileWriter;
     
       // Opening the file in write mode
       fileWriter.open("sample.txt");
       cout << "Enter data to write into the file:";
     
       // Write the given input into the file
       fileWriter << buffer << endl;
     
       // Closing the opened file
       fileWriter.close();
     
       return 1;
   }
   

3. 使用CreateThread函数创建两个线程，以从文件写入和读取数据
4. 使用WaitForSingleObject等待，直到指定的对象处于发信号状态或超时间隔过去。

下面是上述程序的实现：

// C++ program for File Writer-Reader
// application using Windows Threads
  
#include 
#include 
#include 
#include 
  
using namespace std;
  
// Thread function used to Read data from the file
DWORD WINAPI ReadFromAFile(PVOID lpParam)
{
    // Create a buffer
    char buffer[1024] = { 0 };
  
    // Creating ifstream object
    ifstream fileReader;
  
    // Opening the file in read mode
    fileReader.open("sample.txt");
  
    // Reading the data into the buffer
    cout << "Reading data from the file:" << endl;
  
    fileReader >> buffer;
    // Printing the data onto the console
    cout << buffer << endl;
  
    // Closing the opened file
    fileReader.close();
    return 1;
}
  
// Thread function used to Write data into the file
DWORD WINAPI WriteIntoAFile(PVOID lpParam)
{
    // Create a buffer
    char buffer[1024] = { 0 };
  
    // Creating ofstream object
    ofstream fileWriter;
  
    // Opening the file in write mode
    fileWriter.open("sample.txt");
    cout << "Enter data to write "
         << "into the file:"
         << endl;
    cin >> buffer;
  
    // Write the given input into the file
    fileWriter << buffer << endl;
  
    // Closing the opened file
    fileWriter.close();
  
    return 1;
}
  
// Driver code
int main()
{
    WSADATA WSAData;
    char buffer[1024];
    DWORD tid;
    ofstream fileWriter;
    ifstream fileReader;
    HANDLE t1, t2;
    int choice, flag = 1;
  
    while (flag) {
        cout << "================================"
             << "========================"
             << "==================" << endl;
        cout << "Select your option"
             << "\t1.Run the application "
             << "\t2.Exit" << endl;
        cin >> choice;
  
        switch (choice) {
  
        case 1:
            // Create the first thread for Writing
            t1 = CreateThread(NULL, 0,
                              WriteIntoAFile,
                              &fileWriter,
                              0, &tid);
            WaitForSingleObject(t1, INFINITE);
  
            // Create the second thread for Reading
            t2 = CreateThread(NULL, 0,
                              ReadFromAFile,
                              &fileReader,
                              0, &tid);
            WaitForSingleObject(t2, INFINITE);
            break;
  
        case 2:
            // Exiting the application
            cout << "Thank you for using"
                 << " the application"
                 << endl;
            flag = 0;
            break;
  
        default:
            // For any query other than 1 and 2
            cout << "Enter a valid query!!"
                 << endl;
        }
    }
    return 0;
}

使用以下命令在cmd中运行应用程序：

g++ MultiThreading.cpp -lws2_32

输出：

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