If you have code that's generating an error, copy and paste that code here. Without seeing the code we can only guess.
How old is the tutorial you're attempting to follow? What kind of a project is it? Current iOS projects have a main() that looks like this:
int main(int argc, char * argv[])
{
@autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([MyAppDelegate class]));
}
}
But even if not an iOS project, the @autoreleasepool { } syntax should be the same I would think if it's an Objective-C file.