The devx package contains various development and build tools, including a C/Cplusplus C++ compiler. Roughly equivalent to Archlinux's base-devel.

Download and install the devx SquashFS SFS file corresponds with the version of Puppy that is in use:

Often the devx file can be downloaded from the same place as the version's ISO. If the Puppy version is a remaster it may use the same devx as the 'parent' Puppy version.

HowtoAddSFStoFullInstall How to Add SFS to Full Installation

Table of Puppy versions and Devx sfs packages