import scala.math._

class Rungegokutty {
  var x:Array[Double] = new Array[Double](11)
  var y:Array[Double] = new Array[Double](11)
  var k:Array[Array[Double]] =  Array.ofDim(11,4)
  var mk:Array[Array[Double]] =  Array.ofDim(11,4)
  var suma:Array[Double] = new Array[Double](11)
  var h:Double = 0

  def func(x:Double,y:Double):Double = {
    h*(y+cos(x/Pi))
  }

  def rK():Unit = {
    for(i<-0 until 11){
      suma(i) = 0
      k(i)(0) = func(x(i),y(i))
      mk(i)(0) = k(i)(0)
      k(i)(1) = func(x(i) + 0.5 * h, y(i) + 0.5 * k(i)(0))
      mk(i)(1) = 2*k(i)(1)
      k(i)(2) = func(x(i)+0.5*h,y(i)+0.5*k(i)(1))
      mk(i)(2) = 2*k(i)(2)
      k(i)(3) = func(x(i)+h,y(i)+0.5*k(i)(2))
      mk(i)(3) = k(i)(3)
      suma(i) = (mk(i)(0)+mk(i)(1)+mk(i)(2)+mk(i)(3))/6
      if(i<10){
        x(i+1) = x(i)+h
        y(i+1) = y(i)+suma(i)
      }
      println("y = "+y(i)+" x = "+f"${x.apply(i)}%1.1f")
    }
  }
}

object Rungegokutty extends App {
  val r = new Rungegokutty()
  r.h = 0.1
  r.x(0) = 1
  r.y(0)= 5.9
  r.rK()
}


------------wynik---------------
y = 5.9 x = 1,0
y = 6.613860698158842 x = 1,1
y = 7.401034753539003 x = 1,2
y = 8.269069623003322 x = 1,3
y = 9.2263011687448 x = 1,4
y = 10.281935982729046 x = 1,5
y = 11.446142295692338 x = 1,6
y = 12.730150365912246 x = 1,7
y = 14.14636333633467 x = 1,8
y = 15.70847965174595 x = 1,9
y = 17.431628241536647 x = 2,0