Try to run a tutorial on cmake from lynda.com

when I try

mkdir xcode
cd xcode
cmake -G "Xcode" ..

I get this error

CMake Error at CMakeLists.txt:107 (message): The C++ compiler does not support C++11 (e.g. std::unique_ptr). make os

installed cmake running on mojave , cmake 3.16.2 and xcode 10.2.

This folder is on my desktop and I can make the Xcode folder in the CMake folder but then the examples are not there

CMakeLists.txt examples glm resources win _FAQs.txt glfw include run.sh xcode

this whats in the folder Exercises folder.

any insight on what's wrong and how to fix this