Type assertion of go interface variables

package main

import "fmt"

func main() {
	var a interface{} = 1

	// Variables participating in type assertions must be interface types , Otherwise, compilation error 

	switch a.(type) {//a.(type) It can only be written in switch In the sentence , Otherwise, compilation error 
	case float32:
		fmt.Println(" A variable is float type ")
	case int:// Will match this case
		fmt.Println(" A variable is int type ")
	default:
		fmt.Println(" Variables are of other types ")
	}

	// Writing a , Security assertion 
	v1,ok:=a.(int)// Assert success 
	fmt.Printf("%v,%T,%v,%T",v1,v1,ok,ok)// Output  1,int,true,bool

	v2,ok:=a.(*int)// Assertion failed 
	fmt.Printf("%v,%T,%v,%T",v2,v2,ok,ok)// Output  <nil>,*int,false,bool

	// Write two , Unsafe assertion 
	v3:=a.(int)// Assert success 
	fmt.Printf("%v,%T",v3,v3)// Output  1,int

	v4:=a.(*int)// Assertion failed  panic: interface conversion: interface {} is main.User, not *main.User
	fmt.Printf("%v,%T",v4,v4)


}