Java 天地·Core Java·Lecture Notes·Unitt 07 - Inheritance and Interfaces

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Content Page # 15

Recall of RandomBall method overriding

For another example of method overriding and inheritance look back at the unit 2 class RandomBall , (in version 8 of the bouncing ball world) which overrode the move() method to be random:

// RandomBall.java
public class RandomBall extends Ball
{ public RandomBall (int newX, int newY, int newRadius,int newXMotion, int newYMotion) {
    // call the Ball constructor
    super( newX, newY, newRadius, newXMotion, newYMotion ); }
public void move()      {
      // 50% chance of chaning X motion
      if( Math.random() > 0.5 )       dx = -dx;       // 50% chance of changing Y motion
      if( Math.random() > 0.5 )       dy = -dy;       // move centre of object       x = x + dx;
      y = y + dy;       }
}
// class RandomBall Back to top