class EulerMethod {
  T0 : static : Float;
  TR : static : Float;
  k : static : Float;
  delta_t : static : Float[];
  n : static : Float;

  function : Main(args : String[]) ~ Nil {
    T0 := 100;
    TR := 20;
    k := 0.07;
    delta_t := [2.0, 5.0, 10.0];
    n := 100;

    f := NewtonCooling(Float) ~ Float;
    for(i := 0; i < delta_t->Size(); i+=1;) {
      IO.Console->Print("delta_t = ")->PrintLine(delta_t[i]);
      Euler(f, T0, n->As(Int), delta_t[i]);
    };
  }

  function : native : NewtonCooling(t : Float) ~ Float {
    return -1 * k * (t-TR);
  }

  function : native : Euler(f : (Float) ~ Float, y : Float, n : Int, h : Float) ~ Nil {
    for(x := 0; x<=n; x+=h;) {
      IO.Console->Print("\t")->Print(x)->Print("\t")->PrintLine(y);
      y += h * f(y);
    };
  }
}