C++ - Boost ASIO網絡服務器/客戶端

我已經編寫了一個客戶端和服務器程序。該程序當前執行以下操作：C++ - Boost ASIO網絡服務器/客戶端

服務器偵聽到終點爲
客戶端連接到
服務器上接受
客戶端接收消息

一個連接發送消息到服務器的連接

我這樣做是異步的。但是，問題是他們只能發送/接收一條消息。之後，他們只是終止。下面是我的代碼：

#include <iostream> 
#include <vector> 
#include<boost/asio.hpp> 

std::vector<char> buff(256); 

void SendHandler(boost::system::error_code ex){ 
    std::cout << " do something here" << std::endl; 
} 

void ReadHandler(boost::system::error_code ex){ 
    std::cout << " print the buffer data..." << std::endl; 
    std::cout << buff.data() << std::endl; 

} 

void Server(){ 
    boost::asio::io_service service; 
    using namespace boost::asio::ip; 
    tcp::endpoint endpoint(tcp::v4(), 4000); 
    tcp::acceptor acceptor(service, endpoint); 
    tcp::socket socket(service); 
    std::cout << "[Server] Waiting for connection" << std::endl; 


    acceptor.accept(socket); 
    std::cout << "[Server] Accepted a connection from client" << std::endl; 

    std::string msg = "Message from server"; 
    socket.async_send(boost::asio::buffer(msg), SendHandler); 
    service.run(); 

} 

void Client(){ 
    boost::asio::io_service service; 
    using namespace boost::asio::ip; 
    tcp::endpoint endpoint(address::from_string("127.0.0.1"), 4000); 
    tcp::socket socket(service); 
    std::cout << "[Client] Connecting to server..." << std::endl; 
    socket.connect(endpoint); 
    std::cout << "[Client] Connection successful" << std::endl; 

    socket.async_read_some(boost::asio::buffer(buff), ReadHandler); 
    service.run(); 
} 

int main(int argc, char **argv) { 
    if(argc == 1){ 
     std::cout << "Please specify s for server or c for client" << std::endl; 
     return -1; 
    } 
    if(argv[1][0] == 's'){ 
     Server(); 
    } 
    else{ 
     Client(); 
    } 
    return 0; 
}

我想這個擴展程序，以便：