import std.stdio;

import std.range;

import std.math;

​

struct Point(T) {

  T x;

  T y;

​

  T distanceTo(Point that) const {

    immutable real xDistance = x - that.x;

    immutable real yDistance = y - that.y;

​

    immutable distance = sqrt((xDistance * xDistance) +

                  (yDistance * yDistance));

    return cast(T) distance;

  }

}

​

Point!T getResponse(T : Point!T)(string question) {

    writefln("%s (Point!%s): ", question, T.stringof);

​

    auto x = getResponse!T(" x");

    auto y = getResponse!T(" y");

​

    return Point!T(x, y);

}

​

void main()

{

  auto point3 = getResponse!(Point!int)("What's the point? ");

  auto point4 = getResponse!(Point!int)("What's the point? ");

  writeln("Distance: ", point3.distanceTo(point4));

}