View Compilation Error

0_0_2856813_15177.cpp: In function `void bfs(int, int, double)':
0_0_2856813_15177.cpp:22: error: `a' undeclared (first use this function)
0_0_2856813_15177.cpp:22: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2856813_15177.cpp:22: error: expected `;' before "for"
0_0_2856813_15177.cpp:22: error: name lookup of `i' changed for new ISO `for' scoping
0_0_2856813_15177.cpp:18: error:   using obsolete binding at `i'
0_0_2856813_15177.cpp:22: error: expected `;' before ')' token