server2.c

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

#define PORT 8080
#define BUFFER_SIZE 1024
#define SCREEN_WIDTH 80

int new_socket;

void *receive_messages(void *arg) {
    char buffer[BUFFER_SIZE];
    while (1) {
        memset(buffer, 0, BUFFER_SIZE);
        int valread = read(new_socket, buffer, BUFFER_SIZE);
        if (valread <= 0) {
            break;
        }
        printf("\r%-*s\n", SCREEN_WIDTH, buffer);
        printf("You: ");
        fflush(stdout);
    }
    return NULL;
}

void *send_messages(void *arg) {
    char buffer[BUFFER_SIZE];
    while (1) {
        printf("You: ");
        fgets(buffer, BUFFER_SIZE, stdin);
        send(new_socket, buffer, strlen(buffer), 0);
        printf("\r%*s\n", SCREEN_WIDTH, buffer);
    }
    return NULL;
}

int main() {
    int server_fd;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);

    pthread_t receive_thread, send_thread;

    // Creating socket file descriptor
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }

    // Forcefully attaching socket to the port 8080
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
        perror("setsockopt");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    // Forcefully attaching socket to the port 8080
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("bind failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        close(server_fd);
        exit(EXIT_FAILURE);
    }
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t *)&addrlen)) < 0) {
        perror("accept");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    pthread_create(&receive_thread, NULL, receive_messages, NULL);
    pthread_create(&send_thread, NULL, send_messages, NULL);

    pthread_join(receive_thread, NULL);
    pthread_join(send_thread, NULL);

    close(new_socket);
    close(server_fd);
    return 0;
}