Simple program in Vala, with errors.

class test0
{
  /* Error upon compiling:
      test0.vala:9.5-9.22: error: Access to instance member `test0.test_exec' denied
           test0.test_exec(q);
           ^^^^^^^^^^^^^^
      Compilation failed: 1 error(s), 0 warning(s)
  */
  public static void main(string[] args)
  {
    test0 argh = new test0();
    stdout.printf("Greetings! How many cycles would you like? INPUT: ");
    int q=0;
    stdin.scanf("%d", out q);
    test0.test_exec(q);
  }


  public void test_exec(int q)
  {
    char choice;
    stdout.printf("Iterative or Recursive [I/R]? INPUT: ");
    stdin.scanf("%c", out choice);
    if(choice == 'I' || choice == 'i' && choice =='R' || choice == 'r')
    {
      stdout.printf("--START--\n");
      if(choice == 'I' || choice == 'i')
      {
        stdout.printf("Processing cycles iteratively.");
        iter_cycle(q);
      }
      if(choice == 'R' || choice == 'r')
      {
        stdout.printf("Processing cycels recursively.");
        recur_cycle(q);
      }
    }
    else
    {
      test_exec(q);
    }
  }

  public void iter_cycle(int q)
  {
    for(int red = q; red > 0 || q > 0 ; red--)
    {
      stdout.printf("Cycle %d\n", red);
      if(red == 0 && q != 0)
      {
        red = q--;
        stdout.printf("--NEXT--\n");
      }
    }
  }

  public void recur_cycle(int q)
  {
    for(int red=q; red > 0; red--)
    {
      stdout.printf("Cycle %d\n", red);
      if(red == 0 && q != 0)
      {
        red = q--;
        stdout.printf("--NEXT--\n");
        recur_cycle(q);
      }
    }
  }
}