Struct vs interface

interface.go

package main

import "fmt"

type student struct{
  name string
  age int
  lastName string
}


type studentI interface{

  GetAge() int
  GetFullName() string
  GetName() string
}


func StudentDetails(si studentI){
 fmt.Println(si)
  fmt.Println("student age",si.GetAge())
  fmt.Println("student Full name", si.GetFullName())
 fmt.Println("student Name", si.GetName())
}


func (s student) GetAge() int {
   return s.age
}

func (s student) GetFullName() string{
  return s.name + s.lastName
}


func (s student)GetName() string{
  return s.name
}



func main(){
    v := student{name: "muthu", age: 22, lastName: "kumar"}
    StudentDetails(v)
}