My C++ solutions for a year 2020. All solutions and guides are done on Linux.
To build use CMake with separate build directory and build with debug information to support debugging with gdb.
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Debug ..
make
Then to run the executables you need to go to the build folder and pipe the puzzle input for it
cd build/dayXX
./dayXX < input