Go ahead and use your tricky questions, but (a) only if you knew the answer before reading it on that website and (b) you desire to screen out qualified people

Go ahead and use your tricky questions, but (a) only if you knew the answer before reading it on that website and (b) you desire to screen out qualified people who avoid the arcane corners of the language. I worked a couple times with a guy who was very smart but also quite arrogant. Each interview was an opportunity for him to show that he was "superior" to the candidate he was interviewing. One that sticks out in my mind was that this arrogant guy used to work at Amdahl and thus was knowledgeable about the IBM 370 instruction set. When the candidate said they had worked as a COBOL programmer on an IBM mainframe, arrogant guy jumped into action. "Ah, so you know the 370? OK, then, when executing the numeric EDIT instruction and the format field is smaller than the number of digits required to hold the argument and there are an odd number of digits after the decimal point, what will the carry flag be set to upon exit?" Of course, the candidate didn't know the answer, and arrogant guy was quite dismissive of the candidate's abilities.