Arduino: 1.8.1 (Windows 10), Board: "Arduino/Genuino Uno"

C:\Users\HARIHA~1\AppData\Local\Temp\ccehc3ra.ltrans0.ltrans.o: In function `setup':

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:189: undefined reference to `PID::SetOutputLimits(double, double)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:190: undefined reference to `PID::SetSampleTime(int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:191: undefined reference to `PID::SetOutputLimits(double, double)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:192: undefined reference to `PID::SetSampleTime(int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:202: undefined reference to `PID::SetTunings(double, double, double)'

C:\Users\HARIHA~1\AppData\Local\Temp\ccehc3ra.ltrans0.ltrans.o: In function `MPUMath':

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:253: undefined reference to `PID::SetMode(int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:254: undefined reference to `PID::SetMode(int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:262: undefined reference to `PID::Compute()'

C:\Users\HARIHA~1\AppData\Local\Temp\ccehc3ra.ltrans0.ltrans.o: In function `loop':

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:223: undefined reference to `PID::SetMode(int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:224: undefined reference to `PID::SetMode(int)'

C:\Users\HARIHA~1\AppData\Local\Temp\ccehc3ra.ltrans2.ltrans.o: In function `__static_initialization_and_destruction_0':

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:57: undefined reference to `PID::PID(double*, double*, double*, double, double, double, int)'

C:\Users\Hariharan T\Desktop\BalancingBotBasicForHarzSR/BalancingBotBasicForHarzSR.ino:84: undefined reference to `PID::PID(double*, double*, double*, double, double, double, int)'

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.