I'm making a battery capacity tester using LEDs. The code I'm using is attached below. Please help me solve the error.
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `write':
sketch/U8glib.h:93: undefined reference to `u8g_DrawGlyph'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `initI2C':
sketch/U8glib.cpp:57: undefined reference to `u8g_dev_sh1106_128x64_i2c'
sketch/U8glib.cpp:57: undefined reference to `u8g_dev_sh1106_128x64_i2c'
sketch/U8glib.cpp:57: undefined reference to `u8g_InitI2C'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `cbegin':
sketch/U8glib.h:53: undefined reference to `u8g_Begin'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `firstPage':
sketch/U8glib.h:107: undefined reference to `u8g_FirstPage'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `setFont':
sketch/U8glib.h:166: undefined reference to `u8g_font_fub14r'
sketch/U8glib.h:166: undefined reference to `u8g_font_fub14r'
sketch/U8glib.h:166: undefined reference to `u8g_SetFont'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `drawStr':
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `nextPage':
sketch/U8glib.h:108: undefined reference to `u8g_NextPage'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino/Genuino Uno.
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `write':
sketch/U8glib.h:93: undefined reference to `u8g_DrawGlyph'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `initI2C':
sketch/U8glib.cpp:57: undefined reference to `u8g_dev_sh1106_128x64_i2c'
sketch/U8glib.cpp:57: undefined reference to `u8g_dev_sh1106_128x64_i2c'
sketch/U8glib.cpp:57: undefined reference to `u8g_InitI2C'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `cbegin':
sketch/U8glib.h:53: undefined reference to `u8g_Begin'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `firstPage':
sketch/U8glib.h:107: undefined reference to `u8g_FirstPage'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `setFont':
sketch/U8glib.h:166: undefined reference to `u8g_font_fub14r'
sketch/U8glib.h:166: undefined reference to `u8g_font_fub14r'
sketch/U8glib.h:166: undefined reference to `u8g_SetFont'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `drawStr':
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
sketch/U8glib.h:171: undefined reference to `u8g_DrawStr'
C:\Users\JAYESH~1\AppData\Local\Temp\cczocZt1.ltrans0.ltrans.o: In function `nextPage':
sketch/U8glib.h:108: undefined reference to `u8g_NextPage'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino/Genuino Uno.