Functions in the Go language learning 6:go language

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A complete function definition form in the Go language is as follows:

Func (t type) funcname (a int) (b,c int) {return)

• 1.func is the keyword that defines the function
• 2. (t type): This part is called the receiver section, which indicates that the function is used for a particular type
• 3.funcname: The name of the function
• 4. (a int): parameters accepted by the function
• 5. (b,c int): function return value, go language function is can return multiple values at the same time
• 6.{return: The body part of the function

There is no need to define function prototypes in the go language, because the go language searches for all files at compile time, so function prototypes do not exist in go. The variables of function in Go are also used in the same way as the C language.
Here's a look at the return of multiple values of the Go function:See an example of a multivalued return:

Func getindexandvalues (shu []int,index  int) (int,int) {x:=index        Y:=shu[index]         return x, y} The function itself does not mean anything, But we can see that it also returns two values X and Ygo functions support named return values, and the named return value can be used directly in the function, so the above function can be rewritten as: Func getindexandvalues (shu []int,index  int) (x int,y int) {X=index        Y=shu[index]         return x, y} if the function returns without parameters, the function will return the current value of the named parameter by default: Func Getindexandvalues (Shu []int,index  int) (x int,y int) {X=index        Y=shu[index]         return} This function, like the function above, returns X, The value of Y the Go function also has a very important function that is delay:

Why do we need to delay the function? Recall a situation in which we open a file read and write in C or another language:

void file ()

{

F=open ("Sagag.txt"),                if (f is empty) {close (f); Return;}......if (read error) {close (f); Return;}......if (read error) {close (f); return;} ...

}

In short, we will encounter a lot of abnormal situation, need close file, so that caused a lot of duplicated code and operation, the go function of the delay function is to solve the problem. Go uses the keyword defer to specify the delay function, go specifies that the delay function is only called when the function that called it exits, so the above code can be rewritten as:

Func file () {    File.Open ("Asdag.txt")    defer file.close () ... .... do   something   return} (".).."

Delay functions can delay not only a single statement, but also a list

For I: = 0; I < 5; i++ {       defer FMT. Printf ("%d", I)}

The actual output of the above function is: 4 3 2 1 0 because the deferred list is in the same advanced post-out mode as the stack. The function values of the Go language support arguments:Defines the form of a function that can accept arguments: Func myfunc (arg ... int) {}, the types of these parameters are all int, in the function body, the variable arg is an int type of slice, and if you do not specify the type of the parameter, the default is an empty interface interface{}.