[C++] TCP/IP 소켓 통신 예제

1. Sever, Client 각각 프로젝트 생성

2. C++에서 제공하는 Socket을 사용하기 위해 ws2_32.lib 추가.

3. Sever.cpp

#include<iostream>

#include<string>

#include<winsock2.h>

using namespace std;

void ShowErrorMessage(string message)

{

cout << "[오류발생]: " << message << '\n';

system("pause");

exit(1);

}

int main()

{

WSADATA wsaData;

SOCKET serverSocket, clientSocket;

SOCKADDR_IN serverAddress, clientAddress;

int serverPort = 9876;

char received[256];

if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) // Winsock을초기화합니다.

ShowErrorMessage("WSAStartup()");

serverSocket = socket(PF_INET, SOCK_STREAM, 0); // TCP 소켓을생성합니다.

if (serverSocket == INVALID_SOCKET)

ShowErrorMessage("socket()");

memset(&serverAddress, 0, sizeof(serverAddress));

serverAddress.sin_family = AF_INET;

serverAddress.sin_addr.s_addr = htonl(INADDR_ANY); // 4바이트정수를네트워크바이트형식으로

serverAddress.sin_port = htons(serverPort); // 2바이트정수네트워크바이트형식으로

if (bind(serverSocket, (SOCKADDR*)&serverAddress, sizeof(serverAddress)) == SOCKET_ERROR)

ShowErrorMessage("bind()");

cout << "[현재상태] bind()\n";

if (listen(serverSocket, 5) == SOCKET_ERROR)

ShowErrorMessage("listen()");

cout << "[현재상태] listen()\n";

int sizeClientAddress = sizeof(clientAddress);

clientSocket = accept(serverSocket, (SOCKADDR*)&clientAddress, &sizeClientAddress);

cout << "[현재상태] accept()\n";

if (clientSocket == INVALID_SOCKET)

ShowErrorMessage("accept()");

while (1) { // 클라이언트의메시지를받아서그대로다시전달합니다.

int length = recv(clientSocket, received, sizeof(received), 0);

received[length] = NULL;

cout << "[클라이언트메시지]: " << received << '\n';

cout << "[메시지전송]: " << received << '\n';

if (strcmp(received, "[exit]") == 0) {

send(clientSocket, received, sizeof(received) - 1, 0);

cout << "[서버종료]\n";

break;

}

send(clientSocket, received, sizeof(received) - 1, 0);

}

closesocket(clientSocket);

closesocket(serverSocket);

WSACleanup();

system("pause");

return 0;

}

4. Client.cpp

#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include<iostream>

#include<string>

#include<winsock2.h>

using namespace std;

void ShowErrorMessage(string message)

{

cout << "[오류발생]: " << message << '\n';

system("pause");

exit(1);

}

int main()

{

WSADATA wsaData;

SOCKET clientSocket;

SOCKADDR_IN serverAddress;

int serverPort = 9876;

char received[256];

string sent;

if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) // Winsock을초기화합니다.

ShowErrorMessage("WSAStartup()");

clientSocket = socket(PF_INET, SOCK_STREAM, 0); // TCP 소켓을생성합니다.

if (clientSocket == INVALID_SOCKET)

ShowErrorMessage("socket()");

memset(&serverAddress, 0, sizeof(serverAddress));

serverAddress.sin_family = AF_INET;

serverAddress.sin_addr.s_addr = inet_addr("127.0.0.1"); // 문자열IP를네트워크바이트형식으로

serverAddress.sin_port = htons(serverPort); // 2바이트정수네트워크바이트형식으로

if (connect(clientSocket, (SOCKADDR*)&serverAddress, sizeof(serverAddress)) == SOCKET_ERROR)

ShowErrorMessage("connect()");

cout << "[현재상태] connect()\n";

while (1) { // 반복적으로서버로메시지를전송하고에코메시지를전달받습니다.

cout << "[메시지전송]: ";

getline(cin, sent);

if (sent == "") continue;

send(clientSocket, sent.c_str(), sent.length(), 0);

int length = recv(clientSocket, received, sizeof(received), 0);

received[length] = '\0';

if (strcmp(received, "[exit]") == 0) {

cout << "[서버종료]\n";

break;

}

cout << "[서버메시지]: " << received << '\n';

}

closesocket(clientSocket);

WSACleanup();

system("pause");

return 0;

}

5. 실행화면.

출처 : https://velog.io/@underlier12/C-16-TCP-%EC%97%90%EC%BD%94-%ED%86%B5%EC%8B%A0