View Compilation Error

0_0_10126871_28600.cpp:15: error: `M_PI' was not declared in this scope
0_0_10126871_28600.cpp: In function `void GetLink()':
0_0_10126871_28600.cpp:77: error: `M_PI' undeclared (first use this function)
0_0_10126871_28600.cpp:77: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10126871_28600.cpp: In function `void Solve()':
0_0_10126871_28600.cpp:179: error: `fout' undeclared (first use this function)