circle.java

来自「java课件 java课件 java课件 java课件」· Java 代码 · 共 20 行

public class Circle{
 private double radius;
  
  public Circle(double r){
  	  this.radius = r;
  }
  public void setRadius(double r){
    radius = r;
}
 public double getRadius(){
    return radius;
}
  public double perimeter(){
    return 2*Math.PI*radius;
  }
  public double area(){
    return Math.PI*radius*radius;
  }
}