array.go

@@ -7,7 +7,7 @@ func change(sliceArr ...string) {
 	sliceArr = append(sliceArr, "playground")
 	fmt.Println(sliceArr)
 }
-func changeArr(arr []int)  {
+func changeArr(arr []int) {
 	arr[2] = 222
 }
 func main() {
@@ -28,7 +28,7 @@ func main() {
 	change(welcome...)
 	fmt.Println(welcome)
 
-	arr1 := [3]int{1,2,3}
+	arr1 := [3]int{1, 2, 3}
 	changeArr(arr1[:])
 	fmt.Println(arr1)
 }

interface.go

 package main
 
+import "fmt"
+
 type salary_calculator interface {
 	calculate_salary() int
 }
@@ -23,6 +25,77 @@ func (c contract) calculate_salary() int {
 	return c.basicpay
 }
 
-func total_expens(s [])  {
-	
+func total_expens(s []salary_calculator) {
+	expense := 0
+	for _, v := range s {
+		expense += v.calculate_salary()
+	}
+	fmt.Println(expense)
+}
+
+func allType(i interface{}) {
+	fmt.Printf("Type = %T , value = %v\n", i, i)
+}
+
+// assest 类型断言
+func assest(i interface{}) {
+	v, ok := i.(int)
+	fmt.Println(v, ok)
+}
+
+// 类型选择
+func findType(i interface{}) {
+	switch i.(type) {
+	case string:
+		fmt.Println("string")
+	case int:
+		fmt.Println("int")
+	case salary_calculator:
+		fmt.Println("salary_calculator")
+	default:
+		fmt.Println("default unknow type")
+	}
+}
+
+// 指针接受者
+type describer interface {
+}
+
+type address struct {
+	city, state string
+}
+
+func (i *address) show_address() {
+	fmt.Printf("%v,%v", i.city, i.state)
+	i.city = "usa"
+}
+
+func main() {
+	a := permanet{
+		1, 1000, 3000,
+	}
+	b := contract{
+		2, 5000,
+	}
+	exployees := []salary_calculator{a, b}
+	total_expens(exployees)
+	c := 9
+	d := ":456"
+	allType(c)
+	allType(d)
+	// 类型断言
+	assest(c)
+	assest(d)
+	// 类型选择
+	findType(c)
+	findType(d)
+	findType(true)
+	findType(a)
+	fmt.Println("==================")
+	AD := address{"china", "1111111.333333"}
+	p := &AD
+	p.show_address()
+	fmt.Println(p, &AD, AD)
 }
+
+// interface is ok