#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

typedef struct {
   int tag;
   int pid;
   int nch;
   int ctag[10];
   int cpid[10];
} cinfo_t;

void printtag ( int t, int d )
{
   int i;

   for (i=d-1; i>=0; --i)
      printf("%c", (t & (1 << i)) ? '1' : '0');
}

cinfo_t createcube ( int d )
{
   int l, ctag, cpid, cno, shift;
   cinfo_t cinfo;

   cinfo.tag = 0;
   cinfo.nch = 0;
   for (l=0; l<d; ++l) {
      shift = (1 << l);
      ctag = cinfo.tag + shift;
      if ((cpid = fork())) {
         cno = cinfo.nch;
         cinfo.ctag[cno] = ctag;
         cinfo.cpid[cno] = cpid;
         ++cinfo.nch;
      } else {
         cinfo.tag = ctag;
         cinfo.nch = 0;
      }
   }
   cinfo.pid = getpid();
   return cinfo;
}

void printcinfo ( cinfo_t cinfo, int d )
{
   int i;

   printf("+++ Process "); printtag(cinfo.tag,d);
   printf(" [%d]: %d children", cinfo.pid, cinfo.nch);
   for (i=0; i<cinfo.nch; ++i) {
      printf("%c ", (i == 0) ? ':' : ',');
      printtag(cinfo.ctag[i],d);
      printf(" [%d]", cinfo.cpid[i]);
   }
   printf("\n");
}

void dowork ()
{
   usleep(500000 + rand() % 2500000);
}

void waitcube ( cinfo_t cinfo, int d )
{
   int i, j, cpid, cno;

   for (i=0; i<cinfo.nch; ++i) {
      cpid = wait(NULL);
      cno = -1;
      for (j=0; j<cinfo.nch; ++j) if (cpid == cinfo.cpid[j]) { cno = j; break; }
      printf("    Process "); printtag(cinfo.tag,d);
      printf(" [%d]: Child ", cinfo.pid);
      printtag(cinfo.ctag[cno],d); printf(" [%d] terminated\n", cpid);
   }
   printf("--- Process "); printtag(cinfo.tag,d);
   printf(" [%d]: Going to terminate\n", cinfo.pid);
}

int main ( int argc, char *argv[] )
{
   int d;
   cinfo_t cinfo;

   d = (argc > 1) ? atoi(argv[1]) : 4;
   if ((d < 0) || (d > 10)) d = 4;
   srand((unsigned int)time(NULL));
   cinfo = createcube(d);
   printcinfo(cinfo,d);
   dowork();
   waitcube(cinfo,d);

   exit(0);
}