The difference between "Swfit" swift and OC two grammar writing single cases

The difference between swift and OC two grammar writing single cases

For example, write a single example of a networktools

(1) OC Write a single case

1+(instancetype) sharednetworktools {2     Static IDinstance;3     4     Staticdispatch_once_t Oncetoken;5     6Dispatch_once (&oncetoken, ^{7Instance =[[Self alloc] init];8         //Here you can do some initialization9     });Ten      One     returninstance; A}

(2) Swift writes a single example

1     //to define a private static member2     //' Let ' is thread-safe3     //This code is lazy to load, and will not run until the first call.4     Private StaticLet instance =Networktools ()5     6     classFunc Sharednetworktools ()Networktools {7         returninstance8}

If you want to initialize some properties beforehand, you can write this

1  Private StaticLet Instance:networktools = {2Let Networktool =Networktools ()3           //This initializes the properties4         5            returnNetworktool6     }()7     8     classFunc Sharednetworktools ()Networktools {9         returninstanceTen}

The difference between "Swfit" swift and OC two grammar writing single cases