View Compilation Error

0_0_10969890_17989.cpp: In function `void dfs2(int, int)':
0_0_10969890_17989.cpp:45: error: `w' undeclared (first use this function)
0_0_10969890_17989.cpp:45: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10969890_17989.cpp: In function `int main()':
0_0_10969890_17989.cpp:76: error: `change' undeclared (first use this function)
0_0_10969890_17989.cpp:76: error: expected `;' before '}' token