View Compilation Error

877160_0_0_1268.cpp: In function `void dfs(int, int)':
877160_0_0_1268.cpp:37: error: `a' undeclared (first use this function)
877160_0_0_1268.cpp:37: error: (Each undeclared identifier is reported only once for each function it appears in.)
877160_0_0_1268.cpp:37: error: expected `;' before "continue"