C++ problem. Create a library with a following function, all of which have three double input A, B, C

Create a library with the following functions, all of which have three "double" inputs A, B, and C: -sum: returns the sum of A, B, and C avg: returns the average of A, B, and C max: returns the maximum of A, B, and C min: returns the minimum of A, B, and C Next, create a program that makes use of your library. Ask the user to input three values, call each function in the library, and output each result