View Compilation Error

0_0_6408287_21592.cpp: In function `int main()':
0_0_6408287_21592.cpp:228: error: `g1' undeclared (first use this function)
0_0_6408287_21592.cpp:228: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6408287_21592.cpp:236: error: `node' undeclared (first use this function)
0_0_6408287_21592.cpp:239: error: `find_components' undeclared (first use this function)