// Experiment 5: TCP Client-Server - send message from client, displayed on server (and vice versa)
// CLIENT side
// Compile: gcc 05_tcp_client_server_msg_client.c -o client
// Run    : ./client   (run AFTER server is started)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define PORT 8080
#define BUF  1024

int main() {
    int sock;
    struct sockaddr_in serv_addr;
    char buffer[BUF] = {0};

    // 1. Create socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("socket"); exit(EXIT_FAILURE);
    }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port   = htons(PORT);

    // 2. Server address (localhost)
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        perror("inet_pton"); exit(EXIT_FAILURE);
    }

    // 3. Connect
    if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
        perror("connect"); exit(EXIT_FAILURE);
    }
    printf("Connected to server.\n");

    // 4. Send to server
    char *msg = "Hello from client!";
    send(sock, msg, strlen(msg), 0);
    printf("Message sent to server.\n");

    // 5. Receive reply
    read(sock, buffer, BUF);
    printf("Reply from server: %s\n", buffer);

    close(sock);
    return 0;
}