Error compiling for board Arduino/Genuino Uno.

It seems to perpetualy state that "Error compiling for board Arduino/Genuino Uno." and I am awfully confused.
Error message-"Arduino: 1.8.5 (Windows 10), Board: "Arduino/Genuino Uno"

C:\Users*****\AppData\Local\Temp\ccjxpa2h.ltrans0.ltrans.o: In function `setup':

E:\Boot things\Aurduino\SIK-Guide-Code-V_3.3\SIK_circuit15_LCDscreen/SIK_circuit15_LCDscreen.ino:54: undefined reference to `getVoltage(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.

Your code which you didn't post is calling a function getVoltage() except that function isn't defined anywhere in your code or the libraries you #included.