C tic-tac-toe

#include <stdio.h>
#include <string.h>
#include <stdbool.h>

typedef struct
{
    int starting_user;
    bool firststep;
    bool rnd;
}play_data;

typedef struct
{
    int *array;
    int size;
    int used;
}Array;

void init(Array *a,int initsize)
{
    a->array=(int*)malloc(sizeof(int)*initsize);
    a->used=0;
    a->size=initsize;
}

void insert(Array *a,int value)
{
    if(a->size==a->used)
    {
        a->size *= 2;
        a->array = realloc(a->array,sizeof(int)*a->size);
    }
    a->array[a->used++]=value;
}

int main(int argc, char* argv[])
{
    play_data pd;
    Array plg;
    char *play[10];

    decide_player(&pd,argv[1]);
  init(&plg,9);

    if(pd.starting_user==1&&pd.firststep != true){useraction();pd.firststep=true;}

   while(true)
   {
      insert(&plg,useraction());
      insert(&plg,robotaction(&plg));
   }

  return 0;
}

int useraction()
{
    int num;
  scanf("%i",num);
  return num;
}

int robotaction(Array *a)
{
    for(int c=0;c<=3;c++)
    {
        printf("%i",c);
    }
    return 0;
}

int random()
{
    srand(time(NULL));
    int r = ( rand() % 9 ) + 1;
    return r;
}


void decide_player(play_data *pd, char *arg)
{
    pd->starting_user = (strcmp(arg,"h1")==0) ? 1 : 2;
}