View Compilation Error

0_0_10499138_9979.cpp: In function `void fd(int, double&, double&)':
0_0_10499138_9979.cpp:7: error: `th' undeclared (first use this function)
0_0_10499138_9979.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10499138_9979.cpp: In function `int main()':
0_0_10499138_9979.cpp:28: error: `l' undeclared (first use this function)