View Compilation Error

0_0_6206820_19699.cpp: In member function `type Graph::mcmf(int, int, int)':
0_0_6206820_19699.cpp:81: error: `G' undeclared (first use this function)
0_0_6206820_19699.cpp:81: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6206820_19699.cpp: At global scope:
0_0_6206820_19699.cpp:98: error: `Graph G' used prior to declaration