View Compilation Error

0_0_8162684_4854.cpp: In member function `double ShortPath::spfa(int, int, int)':
0_0_8162684_4854.cpp:52: error: `f' undeclared (first use this function)
0_0_8162684_4854.cpp:52: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8162684_4854.cpp:52: error: `r' undeclared (first use this function)