prog.l_ada/TMP/Practice/sem25.10/c_inet.c

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

//./client_app stud*** "port"

#define DATA "Hello, World!"
 
int main(int argc, char *argv[]){
  int sock;
  struct sockaddr_in server;
  struct hostent *hp;
  char buf[1024];

  if (argc < 3) {
     printf("c_inet hostname port [data]\n");
     _exit(1);
  }
 
  if((sock = socket( AF_INET, SOCK_STREAM, 0)) == -1) {
     perror("opening stream socket");
     exit(1);
  }

  hp=malloc(sizeof(struct hostent));

  server.sin_family = AF_INET;
  hp = gethostbyname(argv[1]);
  if (hp == (struct hostent *) 0) {
     fprintf(stderr, "%s: unknown host\n", argv[1]);
     exit(2);
  }
  memcpy((char *) &server.sin_addr, (char *) hp->h_addr, hp->h_length);
  server.sin_port = htons(atoi(argv[2]));
  if (connect(sock, (struct sockaddr *) &server, sizeof server) == -1) {
    perror("connecting stream socket");
    exit(1);
  }
  getchar();
  memset(buf,0,1024);
  if (argc > 3){
    printf("[%s]\n",argv[3]);
    strcpy(buf,argv[3]);
  }else{
    strcpy(buf,DATA);
  }
  if (write(sock, buf, strlen(buf)) == -1)
     perror("writing on stream socket");
  close(sock);
  exit(0);
}