Ausgabe aller IP-Adressen

#include <regex>

#include <iostream>

#include <string>

#include <array>

using namespace std;

int main() 

{

    auto re_ipv4 = std::regex(R"""((?:(?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})))""");

    cout << " \n\n Verwaltung von IP-Adressen \n\n";

    std::cout << "Bitte IP-Adresse eingeben:\n";

    string s;

    while (std::getline(std::cin, s)) {

        if (std::regex_match(s, re_ipv4))

            cout << "Ihre IP-Adresse wurde Ueberprueft\n" << "Ihre IP-Adresse ist Gueltig\n";

        else

            cout << "Ihre IP-Adresse ist Ungueltig\n";

        cout << "Eine weitere IP-Adresse eingeben\n";

        break;

    }

    {  

        auto re_ipv4 = std::regex(R"""((?:(?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})))""");

        string s;

        while (std::getline(std::cin, s)) {

            if (std::regex_match(s, re_ipv4))

                cout << "Ihre IP-Adresse wurde Ueberprueft\n" << "Ihre IP-Adresse ist Gueltig\n" << "Eine weitere IP-Adresse eingeben\n";

            else

                cout << "Ihre IP-Adresse ist Ungueltig\n";

                break;

        }

    }

    {  

        auto re_ipv4 = std::regex(R"""((?:(?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})))""");

        string s;

        while (std::getline(std::cin, s)) {

            if (std::regex_match(s, re_ipv4))

                cout << "Ihre IP-Adresse wurde Ueberprueft\n" << "Ihre IP-Adresse ist Gueltig\n";

            else

                cout << "Ihre IP-Adresse ist Ungueltig\n";

                break;

        }

    }

    cout << "Das Programm ist abgeschlossen.\n";

    return 0;

}

#include <sys/socket.h> 

#include <netinet/in.h> 

#include <arpa/inet.h> 

in_addr_t inet_addr( const char * cp );

#include <sys/socket.h> 

#include <netinet/in.h> 

#include <arpa/inet.h> 

char * inet_ntoa( struct in_addr in );

struct in_addr s; s.s_addr = 16777343; // 127.0.0.1 als int 

printf("IP-Adresse schoen formatiert: %s\n", inet_ntoa(s));

#define _DEFAULT_SOURCE

#include <sys/types.h>

#include <sys/socket.h>

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <assert.h>

#include <stdbool.h>

struct my_addr_entry {

  struct addrinfo* info;

};

struct addr_list {

  size_t count, size;

  struct my_addr_entry* list;

};

bool addr_list_add(struct addr_list* list, const struct my_addr_entry* entry){

  size_t count = list->count + 1;

  if(count > list->size){

    size_t new_size = list->size ? list->size * 2 : 1; // Size doubling strategy, to reduce number of reallocs needed

    assert(count <= new_size);

    struct my_addr_entry* ptr = realloc(list->list, sizeof(*list->list) * new_size);

    if(!ptr)

      return false;

    list->list = ptr;

    list->size = new_size;

  }

  list->list[count-1] = *entry;

  list->count = count;

  return true;

}

int main(){

  char input[256];

  struct addr_list list = {0};

  while(fgets(input,sizeof(input),stdin)){

    if(!strcmp(input,"\n"))

      break;

    if(input[strlen(input)-1]=='\n')

      input[strlen(input)-1] = 0;

    struct addrinfo* result = 0;

    int ret = getaddrinfo(input, 0, &(struct addrinfo){.ai_flags=AI_CANONNAME, .ai_socktype=SOCK_STREAM}, &result);

    if(ret){

      fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));

      continue;

    }

    struct my_addr_entry entry = {

      .info = result

    };

    if(!addr_list_add(&list, &entry)){

      perror("addr_list_add failed");

      freeaddrinfo(result);

      break;

    }

  }

  for(size_t i=0,n=list.count; i<n; i++){

    struct my_addr_entry* entry = &list.list[i];

    printf("%s", entry->info->ai_canonname);

    for(struct addrinfo* rp = entry->info; rp != NULL; rp = rp->ai_next){

      char hbuf[NI_MAXHOST];

      if(getnameinfo(rp->ai_addr, rp->ai_addrlen, hbuf, sizeof(hbuf), 0, 0, NI_NUMERICHOST) == 0)

        printf(" %s", hbuf);

    }

    puts("");

  }

  for(size_t i=0,n=list.count; i<n; i++){

    struct my_addr_entry* entry = &list.list[i];

    freeaddrinfo(entry->info);

  }

  free(list.list);

  memset(&list,0,sizeof(list));

  return 0;

}