Error Compiling Example C++ mex files

I want to compile a Mathworks provided C++ mex file in visual studio. The example program is arrayProduct.cpp, available here: https://www.mathworks.com/help/matlab/matlab_external/c-mex-functions.html

I follow the advice in the links below to correctly set up the Visual Studio Environment:

https://stackoverflow.com/questions/16716821/how-to-build-mex-file-directly-in-visual-studio

https://www.mathworks.com/matlabcentral/answers/406574-how-can-i-compile-a-c-program-that-uses-matlab-engine-c-api-in-visual-studio-2017

When I compile in visual studio, the compiler returns the error: LNK1561 entry point must be defined

Previous advice states that the mex file needs a function input, e.g. void mexFunction(output,input). But the MATLAB example doesn't provide that.

What am I missing?