Arduino IDE Error - 'Error Compiling For Board Arduino Uno

I'm trying to upload some code to an Arduino Uno, but keep getting this error. Have had it with other codes too but managed to fix the issue by randomly changing bits and hoping :sweat_smile:. I can't work out how to fix it this time. Code posted below.
Cheers!

"Arduino: 1.8.12 (Windows Store 1.8.33.0) (Windows 10), Board: "Arduino Uno"
C:\Users\tomba\AppData\Local\Temp\ccjHjeVg.ltrans0.ltrans.o: In function main':* *C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.33.0_x86__mdqgnx93n4wtt\hardware\arduino\avr\cores\arduino/main.cpp:46: undefined reference to loop'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino Uno."

Turnstile_LEDs_Code.ino (1.34 KB)

Every Arduino sketch must have a setup() and a loop() function. Even if you don't want to put any code in the function, you still must define the empty function. Your sketch does not have a loop() function, thus the error.