良葛格java學習點滴1

http://caterpillar.onlyfun.net/GossipCN/JavaGossip-V1/JavaGossip.htm

物件導向----使用類別（Class）定義物件中的例子

class Ball
{
    private String name;

 //private double radius;
 private float radius;
 
    public Ball()
 {
    //this(1.5, "redBall");
    this("redBall", 1.5);
 }

    public Ball(String ballName, float ballRadius)
 //public Ball(String ballName, double ballRadius)
 {
     this.name = ballName;

  this.radius = ballRadius;
 }

    public void setBallName(String ballName)
 {
     this.name = ballName;
 }

    //public void setBallRadius(double ballRadius)
 public void setBallRadius(float ballRadius)
 {
     this.radius = ballRadius;
 }

    public String getBallName()
 {
     return name;
 }

 //public double getBallRadius()
 public float getBallRadius()
 {
     return radius;
 }
}

class SimpleBall
{
 //
 public static void main(String[] args)
 {
  Ball ball = new Ball();

     System.out.print("ballname = " + ball.getBallName());

  System.out.print("ballRadius = " + ball.getBallRadius());
 }
}

 編譯結果：

D:/demo/java>javac SimpleBall.java
SimpleBall.java:11: cannot find symbol
symbol  : constructor Ball(java.lang.String,double)
location: class Ball
           this("redBall", 1.5);
           ^
1 error

將float --->double則一切都可以了！ 在這裏先記下了！