Go语言基础函数基本用法及示例详解

func 函数名称( 参数列表] ) (返回值列表]){
  执行语句
}

func add()

func add(a, b int) int

func swap(x,y int) int  {
	var temp int
	temp = x
	x = y
	y = temp
    return  temp
}

func swap(x *int ,y *int) {
   var temp int
   temp = *x   //保存x地址上的值
   *x = *y    //将y值赋给x
   *y = temp  //将temp值赋给y
}

func funcName(arg ...type) {
}

func sum(numbers ...int) int {
    s := 0
    for i:= range numbers {
        s += numbers[i]
    }
    return s
}

func function(a, b int, f func(a,b int) int) int{
  return f(a, b)
}

//需要导包 reflect runtime
func apply(op func(...int) int, a, b int) (int, string){
   p := reflect.ValueOf(op).Pointer()
   opName := runtime.FuncForPC(p).Name();
   return op(a, b), opName
}

func eavl(a, b int) (int, int) {
	 return a +b, a-b
}

q, _ = eavl(2, 1)

func(x，y int) int {
	return x + y
}

f := func() int {
    ...
}

func (a,b int) int {
    return a+b
}(1,2)

 type Greeting func(name string) string

func (g Greeting) say(n string) {
    fmt.Println(g(n))
}

package main
import "fmt"
import "reflect"
import "runtime"
// 一、函数参数
/*有参数有返回*/
func add(a, b int) int {
	return a+b
}
/*函数值传递*/
// func swap(x,y int) int  {
//     var temp int
//     temp = x
//     x = y
//     y = temp
//     return  temp
// }
/*函数引用传递*/
func swap(x *int ,y *int) {
   var temp int
   temp = *x   //保存x地址上的值
   *x = *y    //将y值赋给x
   *y = temp  //将temp值赋给y
}
/*可变参数列表 无默认参数*/
func sum(numbers ...int) int {
    s := 0
    for i:= range numbers {
        s += numbers[i]
    }
    return s
}
/*函数作为参数*/
func function(a, b int, f func(a,b int) int) int{
  return f(a, b)
}
//需要导包 reflect runtime
func apply(op func(...int) int, a, b int) (int, string){
    p := reflect.ValueOf(op).Pointer()
    opName := runtime.FuncForPC(p).Name();
    return op(a, b), opName
}
// 一、返回值
/*多个返回值*/
func eavl(a, b int) (int, int) {
		 return a +b, a-b
}
func main() {
	a,b:=20,5
	fmt.Println(add(a, b))
	swap(&a,&b)
	fmt.Println(a,b)
	fmt.Println(sum(a,b))
	fmt.Println(function(a,b,add))
	fmt.Println(apply(sum,a,b))
	fmt.Println(eavl(a,b))
	q, _ := eavl(a, b)
	fmt.Println(q)
}