Learning Swift from scratch (day 23)--trailing closures

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A closure expression can be passed as a function parameter, and if the closure expression is long, it affects the readability of the program. A trailing closure is a closure expression that is written after the function brackets, and the function supports calling it as the last argument.

Let's look at a sample code:

func calculate (Opr:string, funn: (Int,Int)-> Int)   {///last parameter Funn is (int,int)-> int function type, Funn can receive the closure expression      switch  (OPR)  {     case  "+"  :        print ("10 +  5 =\ (Funn (10,5))     default:         Print ("10 - 5 =\ (Funn (10,5))")     }} calculate ("+", funn: {(A:Int,  b:int)  -> int in return a + b    //call Calculate ("+") {(a:int, b:int)-> int in return a + b }//call, this form is the trailing closure calculate ("+ ")  {$0 + $1 }  //called, which is the trailing closure 

It is important to note that closures must be the last parameter of the parameter list, if Calculate functions are defined in the following form:

func Calculate (funn: (int,int) ->int, opr:string) {

...

}

Since the closure expression is not the last argument, the call Calculate functions cannot be written using trailing closures.

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Learning Swift from scratch (day 23)--trailing closures