View Compilation Error

0_0_2228152_18622.cpp: In function `void dfs(int, int, int, int)':
0_0_2228152_18622.cpp:8: error: `c' undeclared (first use this function)
0_0_2228152_18622.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2228152_18622.cpp:11: error: `r' undeclared (first use this function)
0_0_2228152_18622.cpp:13: error: `ans' undeclared (first use this function)
0_0_2228152_18622.cpp: In function `int main()':
0_0_2228152_18622.cpp:40: error: `c' undeclared (first use this function)
0_0_2228152_18622.cpp:43: error: `r' undeclared (first use this function)
0_0_2228152_18622.cpp:46: error: `ans' undeclared (first use this function)