c - Have wrong(unwanted) values in pointer array elemnt -

i have pointer array named ipn_details has type ip_details:

typedef struct {    char name[64];    char ip[16];     char flags;     char mac[17] ;   } ip_details; 

after calling function get_ip_details when print elements of ipn_details contains wrong value element of mac whenever array contains more 1 member. (all other elements have right values expected.) example, when array has 2 member value of mac in first member concatenated of last characters of name of second member.

first member: name=mina ip=9.9.9.9 flags=a mac=3f:fd:df:fdakh

second member: name=simakh ip=9.9.9.1 flags=ab mac=3f:gv:hj:fd

i have tried debug code using gdbafter memcpy line , printed elemnt of mac , contains right value,i have no idea why contains wrong value when print using cout (i call cout after calling function get_ip_details). printed contents of ipn_details array after memcpy line using gdb. right, think problem not relate function extract_ip.

int get_ip_details(ip_details **ipn_details, int *ip_details_len)  {      int_details *int_details_list=0;      int int_details_list_len = 0;      int ret =       get_int_details(&int_details_list,&int_details_list_len,"eth");      if(ret == 0)      {          int k = 0;          for(int i=0; < int_details_list_len; i++)          {             ip_details * ipn_details=0;             int ipn_details_len=0;             int int_index = int_details_list[i].index;             extract_ip(int_index,              &ipn_details,&ipn_details_len);   // here read ipn_details_len number of members ipn_details array using function   /*  * wanna add members 1 one array ip_details(using loop j),   * increase allocated   * memory of array using realloc function , memcpy members   * ipn_details function ip_details, 1 one  */               if (ipn_details_len != 0)             {                 *ip_details_len += ipn_details_len;                 *ip_details = (ip_details *)realloc(*ip_details,                 (*ip_details_len) *  sizeof(ip_details));                    for(int j=0; j < ipn_details_len; j++)                 {                     memcpy(&((*ip_details)[k]), &                     (ipn_details[j]),sizeof(ip_details));                     k++;                 }             }             free(ipn_details);            }           free(int_details_list);       } } 

i call function this:

ip_details* ips_details=0; int ips_details_len; get_ip_details(&ips_details, &ips_details_len); for(int i=0; < ips_details_len; i++){     cout << string(ips_details[i].name) << "-"<<      string(ips_details[i].ip_address) << "-"  <<      string(ips_details[i].mac_address) << "-" <<      ips_details[i].flags << endl;  } 

i can't code compile because missing int_details, get_int_details, , extract_ip. can please include definitions (or replace them hard-coded values instead of function calls) can compile , recreate/fix problem?

my suspicion aren't allocating enough space ip_details pointer, end writing beyond allocated space, , second member mention overwriting wrote in first member because memory in first member resides not reserved.

a quick observation, have 17-char array reserved mac, , try print string 14 characters long. i'm assuming don't null terminate string supposed to before reading cout ... string(...). string function going read until finds null-terminator, or reads 17 chars, whichever comes first. that's why reads farther should, 3 undefined characters @ end of string when print it. reason why 3 akh take bit more logic/information, thing doesn't matter are, undefined territory , null terminator should end string before that.