Higher order function

A function is called Higher Order Function if it contains other functions as a parameter or returns a function as an output i.e, the functions that operate with another functions are known as Higher order Functions. It is worth knowing that higher order function is applicable for functions and methods as well that takes functions as parameter or returns a function as a result.
 

The map function is a classic example of a higher order function.

object demo
{
  def doubleValue = (x: Int) => x * x
  def main(args:Array[String])
  {
    val list = List(1,2,3)
    val doubledList = list.map(x => doubleValue(x))
    print(doubledList)
  }

 

Create your own Higher order Function

object demo
{
  def addition(f: (Int, Int) => Int,a: Int, b:Int): Int = f(a,b)
  val squareSum = (x: Int, y: Int) => (x*x + y*y)
  def main(args:Array[String])
  {
    val squaredSum = addition(squareSum, 1,2)
    print(squaredSum)
  }
}

 

 

object demo
{
    def main(args: Array[String])
    {
        val names = Set("Sunil","Akhil","Rakhi")
        def captainDesignation = (y: String) => "Captain " + y
        val result = names.map(y => captainDesignation(y))
        println("Multiplied List is: " + result)
    }
}

OutPut:-

Multiplied List is: Set(Captain Sunil, Captain Akhil, Captain Rakhi)

Find the Square root of the Function
object demo
{
  def main(args :Array[String])
   {
     val lst=List(1,2,3,4,5,6)
     def dbl=(x:Int)=> x*x
     val result=lst.map(x=> dbl(x))
     println("Multiplied List is: " + result)
   }
}
OutPut:-

Multiplied List is: List(1, 4, 9, 16, 25, 36)

Find the Square root of the Function

object demo
{
  def main(args:Array[String]){
    def addition(f: (Int, Int) => Int,a: Int, b:Int): Int = f(a,b)
    val squareSum = (x: Int, y: Int) => (x*x + y*y)
    val cubeSum = (x: Int, y: Int) => (x*x*x + y*y*y)
    val intSum = (x: Int, y: Int) => (x + y)
    val squaredSum = addition(squareSum, 1, 2)
    val cubedSum = addition(cubeSum, 1, 2)
    val normalSum = addition(intSum, 1, 2)
    println (squaredSum)
    println (cubedSum)
    println (normalSum)
  }
}