You know how you can select Debug or Release for the build? Those are two different configurations and the output for each one goes into a different folder. You can open the Configuration Manager and create additional configurations if you so desire. From the Compile page of the project properties, you can add custom compilation constants for certain configurations and then use those constants in your code to include and exclude certain code based on the current configuration. When it's time to build, you select one configuration and build, then select another configuration and build again. Go to the bin folder and get the two separate outputs from the two separate subfolders.