Here is a part of a statement, it might be incorrect, I don't remember the exact statement. Please tell me what the double exclamation marks means and what about the double percentages. Here is the code. if (!(!d = %%d)) else ... ( not spot-on, don't remember) I think of this as miscellaneous material in C language. Is there any other miscellaneous stuff like this in 'C' that I should know? Where can I find such material in written form, so that I could read about it and gain knowledge? Thank you very much.