3 Do each of the following: a) Write the function header for a function `exchange` that takes two pointers to floating-point numbers `x` and `y` as parameters and does not return a value. b) Write the function prototype for the function in part (a). c) Write the function header for a function `evaluate` that returns an integer and that takes as parameters integer `x` and a pointer to function `poly`, which represents a function that takes an integer parameter and returns an integer. d) Write the