not working for Arduino Mega2560

[rkv006]

hi,

when i try to run this SerialScale example i got this error

C:\Users\admin\AppData\Local\Temp\ccaxVJAp.ltrans0.ltrans.o: In function global constructors keyed to 65535_0_SerialScale.ino.cpp.o.1745': <artificial>:(.text.startup+0x60): undefined reference to Hx711::Hx711(unsigned char, unsigned char)'
C:\Users\admin\AppData\Local\Temp\ccaxVJAp.ltrans0.ltrans.o: In function loop': C:\Users\admin\Desktop\rakesh\hx711\examples\SerialScale/SerialScale.ino:26: undefined reference to Hx711::getGram()'
C:\Users\admin\AppData\Local\Temp\ccaxVJAp.ltrans0.ltrans.o: In function __static_initialization_and_destruction_0': C:\Users\admin\Desktop\rakesh\hx711\examples\SerialScale/SerialScale.ino:16: undefined reference to Hx711::~Hx711()'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino Mega or Mega 2560.

how do we solve this issue
please give a reply :(