The factorial function is defined as: 0!= 1 n! 1-2-3. (n-2)(n-1) n a) Write a C++ function that will return n. The input to the function will be an integer n and the function will return n! io single precision. b) Repeat (a) but this time the function will return n! in double precision. c) Use these function in a program that display 0 to 5 factorial twice: once using the single precision function and once using the double precision function.