finish Q4b

src/Q4.java

@@ -40,6 +40,10 @@ public class Q4 extends AbstractGame {
     private double playerDirectionX = 0,
                    playerDirectionY = 0;
 
+    // (b) Moving in direction (xd; yd) by one step:
+    //      add STEP_SIZE * xd to x1;
+    //      add STEP_SIZE * yd to y1;
+
     /**
      * calculate the direction for the player based on the input point w.r.t. player's location
      * @param Dest destination for the player to move to
@@ -64,6 +68,9 @@ public class Q4 extends AbstractGame {
             if (input.wasPressed(Keys.ENTER)) {
                 // (a)
                 this.setPlayerDirectionTo(BALL_POSITION);
+                // (b)
+                playerX += STEP_SIZE * this.playerDirectionX;
+                playerY += STEP_SIZE * this.playerDirectionY;
             }
 
             if (new Point(playerX, playerY).distanceTo(BALL_POSITION) <= SCORE_DISTANCE) {