View Compilation Error

0_0_4186241_26500.cpp: In function `int main()':
0_0_4186241_26500.cpp:54: error: `lx' undeclared (first use this function)
0_0_4186241_26500.cpp:54: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4186241_26500.cpp:54: error: `rx' undeclared (first use this function)
0_0_4186241_26500.cpp:55: error: `ly' undeclared (first use this function)
0_0_4186241_26500.cpp:55: error: `ry' undeclared (first use this function)