7b) UDP Client-Server Communication (Ubuntu/Linux)

Files:
- server.cpp (UDP Server)
- client.cpp (UDP Client)

------------------------------------------------------------
SERVER (server.cpp):

#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
using namespace std;

int main() {
    int serverSocket = socket(AF_INET, SOCK_DGRAM, 0);

    sockaddr_in serverAddr{};
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(5001);

    bind(serverSocket, (sockaddr*)&serverAddr, sizeof(serverAddr));

    char buffer[1024];
    sockaddr_in clientAddr;
    socklen_t clientAddrSize = sizeof(clientAddr);

    cout << "[+] UDP Server listening on port 5001..." << endl;

    while (true) {
        int bytesReceived = recvfrom(serverSocket, buffer, sizeof(buffer) - 1, 0,
                                     (sockaddr*)&clientAddr, &clientAddrSize);
        if (bytesReceived > 0) {
            buffer[bytesReceived] = '\0';
            cout << "Message from client: " << buffer << endl;
        }
    }

    close(serverSocket);
    return 0;
}


-------------------------------------------------------------------

CLIENT (client.cpp):

#include <iostream>
#include <unistd.h>
#include <arpa/inet.h>
#include <cstring>
using namespace std;

int main() {
    int clientSocket = socket(AF_INET, SOCK_DGRAM, 0);

    sockaddr_in serverAddr{};
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(5001);
    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

    string message;
    cout << "Enter message to send: ";
    getline(cin, message);

    sendto(clientSocket, message.c_str(), message.length(), 0,
           (sockaddr*)&serverAddr, sizeof(serverAddr));

    cout << "Message sent!" << endl;

    close(clientSocket);
    return 0;
}
-----------------------------------------------------------------
Terminal Command (Ubuntu):
1) g++ server.cpp -o server
2) ./server

Terminal Command (Ubuntu):
1) g++ client.cpp -o client
2) ./client