#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>

#define MAXLINE 4096 /*max text line length*/
#define SERV_PORT 3000 /*port*/
#define LISTENQ 8 /*maximum number of client connections */

int main (int argc, char **argv)
{
    int listenfd, connfd, n;
    socklen_t clilen;
    char buf[MAXLINE];
    struct sockaddr_in cliaddr, servaddr;

    //creation of the socket
    listenfd = socket (AF_INET, SOCK_STREAM, 0);

    //preparation of the socket address
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERV_PORT);

    bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

    listen(listenfd, LISTENQ);

    printf("%sn","Server running...waiting for connections.");

    for ( ; ; ) {

        clilen = sizeof(cliaddr);
        connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
        printf("%sn","Received request...");

        while ( (n = recv(connfd, buf, MAXLINE,0)) > 0)  {
            printf("%s","String received from and resent to the client:");
            puts(buf);
            send(connfd, buf, n, 0);
        }

        if (n < 0) {
            perror("Read error");
            exit(1);
        }
        close(connfd);

    }
    //close listening socket
    close(listenfd);

}

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>


#define MAXLINE 4096 /*max text line length*/
#define SERV_PORT 3000 /*port*/

int
main(int argc, char **argv)
{
    int sockfd;
    struct sockaddr_in servaddr;
    char sendline[MAXLINE], recvline[MAXLINE];

    //basic check of the arguments
    //additional checks can be inserted
    if (argc !=2) {
        perror("Usage: TCPClient <IP address of the server");
        exit(1);
    }

    //Create a socket for the client
    //If sockfd<0 there was an error in the creation of the socket
    if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) <0) {
        perror("Problem in creating the socket");
        exit(2);
    }

    //Creation of the socket
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr= inet_addr(argv[1]);
    servaddr.sin_port =  htons(SERV_PORT); //convert to big-endian order

    //Connection of the client to the socket
    if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr))<0) {
        perror("Problem in connecting to the server");
        exit(3);
    }

    while (fgets(sendline, MAXLINE, stdin) != NULL) {

        send(sockfd, sendline, strlen(sendline), 0);

        if (recv(sockfd, recvline, MAXLINE,0) == 0){
            //error: server terminated prematurely
            perror("The server terminated prematurely");
            exit(4);
        }
        printf("%s", "String received from the server: ");
        fputs(recvline, stdout);
    }

    exit(0);
}

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>


#define MAXLINE 4096 /*max text line length*/
#define SERV_PORT 3000 /*port*/

int
main(int argc, char **argv)
{
 int sockfd;
 struct sockaddr_in servaddr;
 char sendline[MAXLINE], recvline[MAXLINE], buffer [256];
//Añadidas por mi//
 float a, b, c;
 a = 0;
 b = 0;
 c = 0;
 c = a + b;

  printf("nPrimer numero: ");
  scanf("%f", &a);
  printf ("nSegundo numero: ");
  scanf ("%f", &b);

sprintf(buffer, "%f", sizeof c, c);


unsigned char len = strlen(buffer);

 //basic check of the arguments
 //additional checks can be inserted
 if (argc !=2) {
  perror("Usage: TCPClient <IP address of the server");
  exit(1);
 }

 //Create a socket for the client
 //If sockfd<0 there was an error in the creation of the socket
 if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) <0) {
  perror("Problem in creating the socket");
  exit(2);
 }

 //Creation of the socket
 memset(&servaddr, 0, sizeof(servaddr));
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr= inet_addr(argv[1]);
 servaddr.sin_port =  htons(SERV_PORT); //convert to big-endian order

 //Connection of the client to the socket
 if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr))<0) {
  perror("Problem in connecting to the server");
  exit(3);
 }

 while (fgets(sendline, MAXLINE, stdin) != NULL) {

  send(sockfd, sendline, strlen(sendline), 0);
  send(sockfd, &len, sizeof len, 0);
  send (sockfd, buffer, sizeof buffer, 0);

  if (recv(sockfd, recvline, MAXLINE,0) == 0){
   //error: server terminated prematurely
   perror("The server terminated prematurely");
   exit(4);
  }
  printf("%s", "String received from the server: ");
  fputs(recvline, stdout);
 }

 exit(0);
}

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>

#define MAXLINE 4096 /*max text line length*/
#define SERV_PORT 3000 /*port*/
#define LISTENQ 8 /*maximum number of client connections */

int main (int argc, char **argv)
{
 float c;
 int listenfd, connfd, n;
 socklen_t clilen;
 char buf[MAXLINE], buf256[256], buffer[256];
 unsigned char len = strlen(buffer);
 struct sockaddr_in cliaddr, servaddr;

 //creation of the socket
 listenfd = socket (AF_INET, SOCK_STREAM, 0);

 //preparation of the socket address
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 servaddr.sin_port = htons(SERV_PORT);

 bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

 listen(listenfd, LISTENQ);

 printf("%sn","Server running...waiting for connections.");

 for ( ; ; ) {

  clilen = sizeof(cliaddr);
  connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
  printf("%sn","Received request...");

  while ( (n = recv(connfd, buf, MAXLINE,0)) > 0)  {
   printf("%s","String received from and resent to the client:");
   puts(buf);


   recv(connfd, &len, sizeof len, 0);
   recv(connfd, buf256, len, 0);
   recv(connfd, buffer, 256, 0);
   buf256[len] = 0;
   sscanf(buffer, "%f", &c);
   puts(buffer);
   printf ("n%f", &c);
   send(connfd, buf, n, 0);
  }

 if (n < 0) {
  perror("Read error");
  exit(1);
 }
 close(connfd);

 }
 //close listening socket
 close(listenfd);
}