import (
   "fmt"
   "math"
)

func main(){
   /* declare a function variable */
   getSquareRoot := func(x float64) float64 {
      return math.Sqrt(x)
   }

   /* use the function */
   fmt.Println(getSquareRoot(9))

}

import "fmt"

func getSequence() func() int {
   i:=0
   return func() int {
      i+=1
   return i 
   }
}

func main(){
   /* nextNumber is now a function with i as 0 */
   nextNumber := getSequence() 

   /* invoke nextNumber to increase i by 1 and return the same */
   fmt.Println(nextNumber())
   fmt.Println(nextNumber())
   fmt.Println(nextNumber())
  
   /* create a new sequence and see the result, i is 0 again*/
   nextNumber1 := getSequence() 
   fmt.Println(nextNumber1())
   fmt.Println(nextNumber1())
}