Programming

#include <stdlib.h>
#include <stdio.h>             /* Basic I/O routines          */
#include <sys/types.h>        /* standard system types       */
#include <netinet/in.h>      /* Internet address structures */
#include <sys/socket.h>     /* socket interface functions  */
#include <netdb.h>         /* host to IP resolution       */
#include <unistd.h>


#define portno  6789             /*  default port of host  */


void error(char *msg);
int main(int argc, char *argv[]);

void error(char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
     int serversocket;
     int newsockfd;
     int clilen;  
     char buffer[4096];
     struct sockaddr_in serv_addr, cli_addr;
    
     /*portno = 80;*/
    
     int n;
    
     
   serversocket = socket(AF_INET, SOCK_STREAM, 0);

    if (serversocket < 0)
       {
        error("ERROR opening socket");
       }
       
       
       

         
         bzero((char *) &serv_addr, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_addr.s_addr = INADDR_ANY;
        /*portno=atoi(argv[1]);*/
         serv_addr.sin_port = htons(portno);
         printf("Socket has port #%d\n", serv_addr.sin_port);
          
   
    
     if (bind(serversocket, (struct sockaddr *) &serv_addr,
              sizeof(serv_addr)) < 0)
              {
              error("ERROR on binding");
              }
             
             
             
     listen(serversocket,5);
    
   
    
     while (1) {
       
         clilen = sizeof(cli_addr);
       
     newsockfd = accept(serversocket,(struct sockaddr *) &cli_addr, &clilen);
                
     if (newsockfd < 0)
          {
          error("ERROR on accept");
          }
    
    
     n = write(newsockfd, buffer, sizeof(buffer)-1);
    
     if (n < 0)
         {
          error("ERROR writing to socket");
          }
          close(newsockfd);
          }
     return 0;
}

#include <stdio.h>		/* Basic I/O routines     */
#include <stdlib.h>
#include <sys/types.h>		/* standard system types  */
#include <sys/socket.h>		/* socket interface functions */
#include <netinet/in.h>			
#include <netdb.h>		 /* host to IP resolution       */
#include <unistd.h>
#include <errno.h>
#include <string.h>

#define portno  6789          /*  default port and host  */
#define MAXDATASIZE 100     /* max number of bytes */


void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int serversocket, numbytes;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    char buffer[MAXDATASIZE];
     int rc;
     
   if (argc < 3)
       {
       fprintf(stderr,"Missing host name\n", argv[0]);
       /*exit(0);*/
       }
       
    
    serversocket = socket(AF_INET, SOCK_STREAM, 0);


    if (serversocket <0)
    {
    perror("socket");
	    exit(1);
     }
   
    
    server = gethostbyname("152.15.92.168");
    if (server == NULL)
     {
        perror("gethostbyname");
	    exit(1);
     }

      serv_addr.sin_family = AF_INET;
      /*bcopy((char *)server->h_addr,
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);*/
       serv_addr.sin_port = htons(portno);
       serv_addr.sin_addr = *((struct in_addr
*)server->h_addr);
	memset(&(serv_addr.sin_zero), '\0', 8);  // zero the
rest of the struct

      rc = connect(serversocket, (struct sockaddr
      *)&serv_addr,sizeof(serv_addr)) ;
      if(rc)
        {
	 perror("connect");
	    exit(1);
	}
	
	if ((numbytes=recv(serversocket, buffer,
MAXDATASIZE-1, 0)) == -1)
	 {
	    		perror("recv");
	    		exit(1);
	 }
		
	buffer[numbytes] = '\0';
	printf("Received: %s",buf);
	//write( 1, buffer,numbytes );
	
	close(serversocket);
	return 0;
    }


	 /*n = send(mysocket,buffer,strlen(buffer),0);

    if (n < 0)
         error("ERROR writing to socket");
	 
	n = read(mysocket,buffer,sizeof(buffer)-1); 
	 if (n < 0)
         error("ERROR reading from socket");

    buffer[n]='\0';  

    close(mysocket);

    printf("%s\n",buffer);

    return 0;
}*/

#include <stdio.h>
 
/* no need to give comment for this headerif anyone doesn't know  abt stdio.h he/she should not programming in C*/

#include <stdlib.h>
#include <sys/types.h> /* standard system types */
#include <sys/socket.h> /* socket interface functions */
#include <netinet/in.h> /* socket struct and Internet Protocol family proto */
#include <netdb.h> /* host to IP resolution */
#include <unistd.h>  
#include <errno.h>  /* for errno and error codes */
#include <string.h>
#include <arpa/inet.h> /* for inet_addr */

#define portno 6789 /* default port and host */
#define MAXDATASIZE 100 /* max number of bytes */


void error(char *msg)
{
perror(msg);
exit(0);
}

int main(int argc, char *argv[])
{
int serversocket, numbytes;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[MAXDATASIZE];
int rc;

if (argc < 3)
{
fprintf(stderr,"Missing host name\n", argv[0]);
/*exit(0);*/
}


serversocket = socket(AF_INET, SOCK_STREAM, 0);


if (serversocket <0)
{
perror("socket");
exit(1);
}


/*server = gethostbyname("152.15.92.168");
if (server == NULL)
{
perror("gethostbyname");
exit(1);
}*/
//no need to call gethostbyname if we know ip address although we can do it like this 

serv_addr.sin_family = AF_INET;
/*bcopy((char *)server->h_addr,
(char *)&serv_addr.sin_addr.s_addr,
server->h_length);*/
serv_addr.sin_port = htons(portno);
/*serv_addr.sin_addr = *((struct in_addr
*)server->h_addr);*/
serv_addr.sin_addr.s_addr = inet_addr("152.15.92.168");
memset(&(serv_addr.sin_zero), '\0', 8); // zero the
rest of the struct

rc = connect(serversocket, (struct sockaddr
*)&serv_addr,sizeof(serv_addr)) ;
//if(rc)

if(rc == -1 )
{
perror("connect");
exit(1);
}

if ((numbytes=recv(serversocket, buffer,
MAXDATASIZE-1, 0)) == -1)
{
perror("recv");
exit(1);
}

buffer[numbytes] = '\0';
printf("Received: %s",buf);
//write( 1, buffer,numbytes );

close(serversocket);
return 0;
}


/*n = send(mysocket,buffer,strlen(buffer),0);

if (n < 0)
error("ERROR writing to socket");

n = read(mysocket,buffer,sizeof(buffer)-1); 
if (n < 0)
error("ERROR reading from socket");

buffer[n]='\0'; 

close(mysocket);

printf("%s\n",buffer);

return 0;
}*/