Testing if somebody groks recursion or pointers is the easiest litmus test to see if somebody "groks" programming. They're not "easy" concepts, and usually peop

Testing if somebody groks recursion or pointers is the easiest litmus test to see if somebody "groks" programming. They're not "easy" concepts, and usually people have had to break through a wall for it to be comfortable with them. They make great interview questions, doesn't need to be long or complex problem, just has to have either pointers or recursion in it.