View Compilation Error

0_0_29243218_17081.cpp: In member function 'void MCMF::minCostMaxFlow(int, int, int&, double&)':
0_0_29243218_17081.cpp:48:37: error: 'pos' was not declared in this scope
             for(int x=t;x!=s;x=edge[pos^1].v){
                                     ^