lcd keypad

It certainly looks cleaner.

It would look even better if you used Tools + Auto Format.

    return;
    
  for (int zz=0; zz<16; zz++) // wipe attempt
  {
    attempt[zz]=0;
  }

We're done. Oh, and by the way do this. No. Doesn't work that way. Nothing after the return statement is executed. And, in a string, you only need one NULL.