Visioo-writer supports document formats such as KWord, and this, an open-source word processor written in C++?
Visioo-Writer: Visioo-writer - The OpenDocument file viewer is a computer program designed to run on multiple operating systems with the explicit ability to view OpenDocument and OpenOffice.org/StarOffice documents. Visioo-Writer:  The goal is to create a small application to open popular and free document formats (e.g., AbiWord, KWord). AbiWord: AbiWord ( ) is a free and open-source software word processor written in C++.
AbiWord