Higher order functions in scala

A function that takes another function as an argument is called a higher order function. Like any other function parameter we give type as Int=>Int which indicates that f expects an integer as input and integer as a return type(........, f:Int=>Int). A complete example is shown which uses a Higher order function and tail recursion.

object Demo{

def main(args:Array[Strings]): Unit ={    

    println(formatResult("Nth febonacci number where value of N is", 5, febonacci))
    println(formatResult("Factorial of ", 7, factorial))
 
  }
  // nth fibonacci number using tail recursions
  def febonacci(n:Int):Int={  
    @annotation.tailrec
    def nextNum(num1: Int, num2:Int, n :Int):Int={
      if(n==0) num2+num1
      else nextNum(num2,num2+num1,n-1)
    }  
   nextNum(0,1,n-2)    
  }

  def factorial(n:Int):Int={
    @annotation.tailrec
    def fact(num:Int, acc:Int):Int={
      if(num<=0) acc
      else fact(num-1, num*acc)
    }  
    fact(n,1)
  }

  def formatResult(name:String, n:Int, g:Int=>Int )={
    val msg="The %s %d is %d"
    msg.format(name,n,g(n))
   
  }
}