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

#define PORT 7000    // Replace with your desired port 7XXX
#define MAXLINE 1024

void handle_client(int connfd) {
    char buffer[MAXLINE];
    int n;

    // Read message from client
    n = read(connfd, buffer, sizeof(buffer) - 1);
    if (n < 0) {
        perror("Read error");
        close(connfd);
        return;
    }
    buffer[n] = '\0'; // Null-terminate the message

    // Print received message
    printf("Received from client: %s\n", buffer);

    // Echo the message back to the client
    write(connfd, buffer, strlen(buffer));

    close(connfd);
}

int main() {
    int listenfd, connfd;
    struct sockaddr_in servaddr, cliaddr;
    socklen_t len;
    pid_t childpid;

    // Create server socket
    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    if (listenfd < 0) {
        perror("Socket creation failed");
        exit(1);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;  // Listen on all available interfaces
    servaddr.sin_port = htons(PORT);

    // Bind the socket to the address and port
    if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
        perror("Bind failed");
        exit(1);
    }

    // Listen for incoming connections
    if (listen(listenfd, 10) < 0) {
        perror("Listen failed");
        exit(1);
    }

    printf("Server started on port %d\n", PORT);

    // Main loop to accept and handle clients
    for (;;) {
        len = sizeof(cliaddr);
        connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &len);
        if (connfd < 0) {
            perror("Accept failed");
            continue;
        }

        if ((childpid = fork()) == 0) {
            close(listenfd);  // Child doesn't need the listening socket
            handle_client(connfd);
            exit(0);  // Child process terminates here
        }

        close(connfd);  // Parent closes the connection socket
        while (waitpid(-1, NULL, WNOHANG) > 0);  // Clean up any terminated child processes
    }

    return 0;
}

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

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

#define PORT 7000   // Replace with the same port used in the server
#define MAXLINE 1024

int main() {
    int sockfd;
    struct sockaddr_in servaddr;
    char send_buffer[MAXLINE] = "Hello from ITxxxxxxxx";
    char recv_buffer[MAXLINE];
    int n;

    // Create socket
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("Socket creation failed");
        exit(1);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(PORT);
    if (inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr) <= 0) {  // Assuming server is on localhost
        perror("Invalid address or address not supported");
        close(sockfd);
        exit(1);
    }

    // Connect to server
    if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
        perror("Connection failed");
        close(sockfd);
        exit(1);
    }

    // Send message to the server
    write(sockfd, send_buffer, strlen(send_buffer));

    // Receive the echo from server
    n = read(sockfd, recv_buffer, MAXLINE);
    if (n < 0) {
        perror("Read error");
        close(sockfd);
        exit(1);
    }
    recv_buffer[n] = '\0';

    // Print the echo response
    printf("Received from server: %s\n", recv_buffer);

    close(sockfd);
    return 0;
}