On behalf of Hez Carty. Fix compile warning in example 31.
On behalf of Hez Carty. Fix compile warning in example 31.


svn path=/trunk/; revision=9653

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot