client

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

int main(int argc, char* argvs[]) {
  int c,l;
  struct sockaddr_in server,server2;
  char ip[20];
  strcpy(ip,argvs[1]);
  int port = atoi(argvs[2]);

  //VERIFICARI-------------------
  if(port<1024 || port>65535){
    printf("Portul nu convine!\n");
    return 1;
  }
  char verif[]="0123456789.";
  int i=0;
  for(i=0;i<strlen(ip);i++){
    if(strchr(verif,ip[i])==0){
      printf("Ip-ul nu convine!\n");
      return 1; //eroare
    }
  }
  //VERIFICARI------------------

  c = socket(AF_INET, SOCK_DGRAM, 0);
  if (c < 0) {
    printf("Eroare la crearea socketului client\n");
    return 1;
  }
  memset(&server, 0, sizeof(server));
  server.sin_port = htons(port);
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = inet_addr(ip);
  l = sizeof(server);

  uint16_t numar;
  printf("Introduceti nr:"); scanf("%hu", &numar);
  numar = htons(numar);
  sendto(c, &numar, sizeof(numar), 0, (struct sockaddr *) &server, sizeof(server));

  recvfrom(c, &numar, sizeof(numar), MSG_WAITALL, (struct sockaddr *) &server, &l);
  printf("%hu\n",ntohs(numar));

  close(c); return 0;
}