Mas esse problema tbm está dando na IDE arduino....na verdade, dps que eu reiniciei o pc agra ta aparecendo outra msg de error
C:\Users\GUILHE~1\AppData\Local\Temp\ccl0UDI8.ltrans0.ltrans.o: In function `main':
C:\Users\guilherme\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.6.18\cores\arduino/main.cpp:35: undefined reference to `init'
C:\Users\GUILHE~1\AppData\Local\Temp\ccl0UDI8.ltrans0.ltrans.o: In function `setup':
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:5: undefined reference to `pinMode'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:6: undefined reference to `pinMode'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:7: undefined reference to `pinMode'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:9: undefined reference to `pinMode'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:10: undefined reference to `pinMode'
C:\Users\GUILHE~1\AppData\Local\Temp\ccl0UDI8.ltrans0.ltrans.o:C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:11: more undefined references to `pinMode' follow
C:\Users\GUILHE~1\AppData\Local\Temp\ccl0UDI8.ltrans0.ltrans.o: In function `loop':
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:16: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:17: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:18: undefined reference to `delay'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:19: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:20: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:21: undefined reference to `delay'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:22: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:23: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:24: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:25: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:26: undefined reference to `delay'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:27: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:28: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:29: undefined reference to `delay'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:30: undefined reference to `digitalWrite'
C:\Users\guilherme\Desktop\ardu\exercicio2/exercicio2.ino:31: undefined reference to `digitalWrite'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino/Genuino Uno.