pdpi

/* Let's pretend we're building a game, which has a physics
 * simulation and a renderer. We're expecting to have a
 * sufficiently large collection of entities that updating in a
 * functional/immutable style is too expensive, but we still want
 * to avoid allowing mutation where it's not strictly required.
 *
 * To this effect, note how `physics` takes a list of MutableEntity,
 * but `render` takes Entity instead. The physics simulation is
 * expected to mutate the entities (to update their (x,y) position
 * according to whatever the simulation wants to do), but rendering

pdpi

import java.util.Scanner;

public class AutoCalc {

    /* It's conventional that field names are in camelCase, so I changed that.
     * 
     * The private keyword means only this class can look at these values. Here,
     * declaring the field as 'static' means that it's a class field, rather than
     * an instance field. The two x and y values are specific to one particular