GO basis of the function

First, the format of the Go language function

Function constitutes the logical structure of the code is executed, the Go language, the basic function of the composition: Keyword func, function name, parameter list, the return value of the function body and return statements, each program contains a number of functions, function is the basic building blocks.

// no return value of the function 
FUNC log (Message String ) {
}

// return a value of the function 
FUNC the Add (A, B int ) int {
     return var1
}
// a plurality of return value of the function 
FUNC Power (name String ) ( int , BOOL ) {
     return   var1, var2
}

// to the return named 
FUNC the Add (A, B int ) (C int ) {
    c = a + b
    return c
}

Returns the value of the multi-function

func main() {
    a := 0
    b := 0
    a, b = addAndMultiply(10, 20)
    fmt.Println("a=", a)
    fmt.Println("b=", b)
}
func addAndMultiply(a, b int) (int, int) {
    return a + b, a * b
}

Second, as a function of the parameter

package main

import "fmt"
import "strings"

func main() {
    str := strToCase("ABDCFSDFE", processLetter)
    fmt.Println(str)
}

// function arguments 
FUNC strToCase (STR String , myfunc FUNC ( String ) String ) String {
     return myfunc (STR)
}

// string alternating parity 
FUNC processLetter (STR String ) (Result String ) {
     for I, value: = Range STR {
         IF I% 2 == 0 {
            result += strings.ToUpper(string(value))
        } else {
            result += strings.ToLower(string(value))
        }
    }
    return result
}

Use type Custom type 

package main

import "fmt"
import "strings"

func main() {
    str := strToCase("ABDCFSDFE", processLetter)
    fmt.Println(str)
}

// function arguments (parameter type defined using type) 
FUNC strToCase (STR String , myfunc processLetterFunc) String {
     return myfunc (STR)
}

// use the type of processLetter () function defines the type of 
type processLetterFunc FUNC ( String ) String

// string alternating parity 
FUNC processLetter (STR String ) (Result String ) {
     for I, value: = Range STR {
         IF I% 2 == 0 {
            result += strings.ToUpper(string(value))
        } else {
            result += strings.ToLower(string(value))
        }
    }
    return result
}

Second, the scope of variables

1, when a local variable with the same name and global variables, local variables priority

// global variable 
var NUM int = 100 
var num2 int = 200 is

func main() {
    Surely, num2: = 1 , 2 
    fmt.Println ( " num = " , num) // num = 1
    fmt.Println("num2=", num2)// num2=2
}