我得到下面的错误。我为什么得到它?我收到此错误。哪里不对?
Duplicate symbol _main in: /Users/AlexBomnd/Library/Developer/Xcode/DerivedData/Backpack-gcnxteerautalugwepzkevaqgtxe/Build/Intermediates/Backpack.build/Debug-iphonesimulator/Backpack.build/Objects-normal/x86_64/main.o /Users/AlexBomnd/Library/Developer/Xcode/DerivedData/Backpack-gcnxteerautalugwepzkevaqgtxe/Build/Intermediates/Backpack.build/Debug-iphonesimulator/Backpack.build/Objects-normal/x86_64/AppDelegate-2D6246B5E95B9D9F.o ld: 1 duplicate symbol for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)