listing7.3.java

来自「java 完全探索的随书源码」· Java 代码 · 共 36 行

import java.awt.Color;

class Circle {
  public Color borderColor;
  private int radius;
  private double area;

  public void setRadius (int rad){
    if ( rad != radius ) {
      radius = rad;
      area = 2.0 * Math.PI * radius;
    }
  }

  public int getRadius(){
    return radius;
  }

  public double area (){
    return area;
  }
}

class GraphicalInterface {
  Circle ball;
  ...

  void animateBall() {
    for (int updateRadius = 0; updateRadius <= 10; updateRadius++){
      ball.setRadius (updateRadius);
      paintBall(ball.area(), ball.borderColor);
      ...
    }
  }
}