使用C ++（Winsock TCP / IP）發送帶有套接字的字符串

Question

我想從客戶端向服務器發送帶有套接字的字符串。

這是客戶端的代碼：

#include <iostream>
#include <winsock.h>
#include <unistd.h>

using namespace std;

int main()
{

//Load socket
WSADATA wsaData;
WSAStartup(0x0202, &wsaData);

//Create first socket
int thisSocket;
struct sockaddr_in destination;

destination.sin_family = AF_INET;
thisSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (thisSocket < 0)
{
    cout << "Socket Creation FAILED!" << endl;
    return 0;
}

//Connect to a host
destination.sin_port = htons(13374);
destination.sin_addr.s_addr = inet_addr("127.0.0.1");
if (connect(thisSocket,(struct sockaddr *)&destination,sizeof(destination))!=0){
    cout << "Socket Connection FAILED!" << endl;
    if (thisSocket) close(thisSocket);
    return 0;
}
cout << "Connected!" << endl;

//Send the socket
//char *buffer = "Hello, this is a socket!";
string buffer = "Hello, this is a socket!";
//send(thisSocket, buffer, (int)strlen(buffer), 0);
send(thisSocket, buffer.c_str(), buffer.length(), 0);

//Close the socket
closesocket(thisSocket);
WSACleanup();

}

這是服務器的代碼：

#include <iostream>
#include <winsock.h>
#include <unistd.h>

using namespace std;

int main()
{

//Load the socket
WSADATA wsaData;
WSAStartup(0x0202, &wsaData);

//Create the first socket
int thisSocket;
struct sockaddr_in destination;

destination.sin_family = AF_INET;
thisSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (thisSocket < 0)
{
    cout << "Socket Creation FAILED!" << endl;
    return 0;
}

//Bind to a socket
destination.sin_port = htons (13374);
destination.sin_addr.s_addr = INADDR_ANY;
if (bind(thisSocket, (struct sockaddr *)&destination, sizeof(destination))     <0){
    cout << "Binding Socket FAILED!" << endl;
    if (thisSocket) close(thisSocket);
    return 0;
}

//Listen on a socket
cout << "Listening on 13374..." << endl;
if (listen(thisSocket, 5)<0){
    cout << "Listening on Socket FAILED!" << endl;
    if (thisSocket) close(thisSocket);
    return 0;
}

//Accept a connection
struct sockaddr_in clientAddress;
int clientSize = sizeof(clientAddress);
thisSocket= accept(thisSocket, (struct sockaddr *)&clientAddress, (int *) &clientSize);
if (thisSocket<0)
{
    cout << "Socket Connection FAILED!" << endl;
    if (thisSocket) close(thisSocket);
    return 0;
}
cout <<"Connection Established!" << endl;

//Receive the socket

char buffer[512];
int newData;
newData = recv(thisSocket, buffer, 512, 0);
cout << newData << endl;

//Close the socket
closesocket(thisSocket);
WSACleanup();

}

如您所見，服務器將收到數字“ 24”。 我怎樣才能得到真正的字符串呢？

Answer 1

recv讀取的數據最終存儲在buffer 。 recv函數返回接收到的字節數，如果連接已關閉則為零，如果發生錯誤則為負值。

閱讀recv參考資料將告訴您所有這些以及更多內容。

請注意，數據不會像字符串一樣終止。 要么像字符串一樣終止它

buffer[newData] = '\0';

在檢查recv函數實際上收到了一些東西之后。 或者，您可以直接構造一個std::string對象：

std::string receivedString{buffer, newData};

除非recv函數實際上收到了一些東西，否則也不要這樣做。

Answer 2

代替：

cout << newData << endl;

做：

cout << buffer << endl;

recv函數返回讀取的字節數，緩沖區保存讀取的字節。