Are you sure you dont mean 'Welsh Powell Graph coloring Algorithm' as in
Welsh, D. J. A.; Powell, M. B. (1967), "An upper bound for the chromatic number of a graph and its application to timetabling problems", The Computer Journal 10 (1): 85–86, doi:10.1093/comjnl/10.1.85
?
I quick Google fails to find 'much' in c++ - you may find translating from java better - this may help as a start point
http://graphstream-project.org/doc/Algorithms/Welsh-Powell_1.0/[
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