Reviewing code on CodeReview doesn't necessarily require actually building it, but it's often helpful to do so in order to evaluate fully. I usually create a CMake project and build from there and this project was how I automated part of the process.
Here's how to use this code. First fetch or create a markdown file (.md file) that contains the full source code for a C++ project. To fetch one from CodeReview, you may use bin/fetchQ which is a Python program designed for this purpose. As an example, let's use http://codereview.stackexchange.com/questions/93775/compile-time-sieve-of-eratosthenes
To fetch the .md file for that question, we need to note the number (93775 in this case) and choose a name (let's say sieve.md). Then use the command fetchQ 93775 sieve.md. This fetches the .md file from the CodeReview site and puts it in the current directory.
Now that we have an .md file, (named sieve.md for this example), we can simply run this code using the command line: autoproject sieve.md
This will automatically parse the sieve.md file and extract the files it finds to a directory tree like this.
sieve
├── build (empty subdirectory)
├── CMakeLists.txt (generated)
└── src
├── CMakeLists.txt (generated)
├── primeconst.cpp (extracted)
├── primeconst.h (extracted)
└── primeconsttest.cpp (extracted)
For much code in many questions, all that is then required is to navigate to the build directory and then type:
cmake ..
make
The executable (if successfully created) will be created in build/src and will be named sieve (or whatever more meaningful name you have given the original .md file). Examples of questions for which this works are http://codereview.stackexchange.com/questions/123489/recursive-breadth-first-search-for-knights-tour and http://codereview.stackexchange.com/questions/78362/hangman-on-the-command-line.
Note that this may not work if there are special things needed by the code in question that are unknown to the software. For instance, this code itself will build because there is a built-in rules that looks for the #include <experimental/filesystem> and, if found, adds the following line to the resulting CMake file:
target_link_libraries(${EXECUTABLE_NAME} stdc++fs)
Other software packages (e.g. some parts of Boost) do not currently have built-in rules.
Note also, that CMake will automatically use the environment variables CFLAGS and CXXFLAGS. My setup, which works well for many programs including this one includes CXXFLAGS="-Wall -Wextra -pedantic". By default, this program generates CMake files that specify C++14 for platforms that recognize the standard compliance level (e.g. gcc and clang but not MSVC).
So far, this program has been tested and run successfully on Linux and Windows.
On most Linux or Windows machines with CMake installed, building will look something like this:
cmake -S . -B build
cmake --build build
The executable will then be in the build/src/ (or build/src/Debug/ for Windows) directory and is named autoproject. Building under Windows with MSVC++ requires MSVC++17 or better.