View Compilation Error

0_0_4944566_20486.cpp: In function `void dfs(int, int)':
0_0_4944566_20486.cpp:12: error: `x' undeclared (first use this function)
0_0_4944566_20486.cpp:12: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4944566_20486.cpp:13: error: `y' undeclared (first use this function)