client.cpp

#include <iostream>
#include <cstring>
#include <cerrno>

//Socket Headers
#include <arpa/inet.h> // For int to network byte order
#include <sys/socket.h> // For socket() methods
#include <netinet/in.h> // For sockaddr_in structure
#include <unistd.h> // For closing the socket

//Helper function similar to server.cpp
static void die(const char* msg) {
    std::cerr << msg << ": " << std::strerror(errno) << std::endl;
    std::exit(1);
}

int main() {
    /* 1. Create a socket descriptor
    This socket is not bound by any specific port, OS will assign a random port */
    int sock_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(sock_fd == -1) die("Socket");

    /* 2. Connect to the server with a specific IP address and port 
    Hardcode the server address and port for now */
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(8080);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    /* 3. Connect to the server
    If the server is running, then this will complete the 3-way handshake and the connection is established */
    if(connect(sock_fd, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) die("Connect");
    
    /* 4. Send data to the server */
    const char* msg = "Hello Server, from the Client!";
    ssize_t bytes_sent = send(sock_fd, msg, strlen(msg), 0);
    if(bytes_sent == -1) die("Send");

    /* 5. Receive data from the server */
    char buffer[4096];
    ssize_t bytes_received = recv(sock_fd, buffer, sizeof(buffer) - 1, 0);
    if(bytes_received == -1) die("recv");

    buffer[bytes_received] = '\0';
    std::cout << "Received from server: " << buffer << std::endl;
    
    /* 6. Close the socket */
    close(sock_fd);

    return 0;
}