Golang problem interface and nil

Interface and Nil

• Serving Code

package mainimport (    "fmt")func main() {    var a interface{}    // 获取console输入    fmt.Scan(&a)    fmt.Println(a)}输出结果：console -------------------------><nil>

• Compare code

package mainimport "fmt"func main() {    var a string    fmt.Scan(&a)    fmt.Println(a)}输出结果：console ------------------------->123123

• Problem description
  The first case: Compile without error, can be executed, but cannot be entered.
  The second situation: Compile no error, can be executed, can be normal operation.
• Answer questions
  Interface type is re-initialized, is not allocating memory space to a variable, equivalent to nil means a null pointer.
  When the string type is defined, the variable is initialized and the memory space is allocated, so when the keyboard enters the value, it can be printed.