tcp_client.c

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

int main(void) {
  int socket_desc;
  struct sockaddr_in server_addr;
  char server_message[100], client_message[100];

  // Clean buffers:
  memset(server_message, '\0', sizeof(server_message));
  memset(client_message, '\0', sizeof(client_message));

  // Create socket:
  socket_desc = socket(AF_INET, SOCK_STREAM, 0);

  if (socket_desc < 0) {
    printf("Unable to create socket\n");
    return -1;
  }

  printf("Socket created successfully\n");

  // Set port and IP the same as server-side:
  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(2000);
  server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

  // Send connection request to the Server:
  if (connect(socket_desc, (struct sockaddr *)&server_addr,
              sizeof(server_addr)) < 0) {
    printf("Unable to connect!\n");
    return -1;
  }

  printf("Connected to Server succesfully.\n");

  // Get input from user
  printf("Enter message: ");
  gets(client_message);

  // Send message to server
  if (send(socket_desc, client_message, strlen(client_message), 0) < 0) {
    printf("Unable to send message.\n");
    return -1;
  }

  // Revieve server's response.
  if (recv(socket_desc, server_message, sizeof(server_message), 0) < 0) {
    printf("Error while receiving server's msg\n");
    return -1;
  }

  printf("Server's response: %s\n", server_message);

  // Close the socket:
  close(socket_desc);
  return 0;
}