Higher-order functions Functions can be returned as return values 入xyx-y Functions can be passed as arguments 06×.×)(xx+1)2 Think about function pointers in C/C++Higher-order functions • Functions can be returned as return values • Functions can be passed as arguments Think about function pointers in C/C++. x. y. x - y (f. x. f x) (x. x + 1) 2