jlab0401b.java

java教程中的编程实例

class Circle{
       double radius;
        public Circle(double r)
         {   radius=r;
          }
        public double area()
          { double s;
            s=3.14*radius*radius;
            return s;
         }
        public double circumference()
        { double c;
          c=2.0*3.14*radius;
          return c;
        }
         public String toString(){
          String s="Circle with radius ";
          s=s+Double.toString(radius);
          return s;
                      }
         public void setRadius(double r)
           {  radius=r;
           }
          public double getRadius()
            { return radius;
              }
}

class JLab0401B{
        public static void main(String[] args){
                   Circle myCircle1=new Circle(2.6);           
                   Circle myCircle2=new Circle(3.1);      
                   System.out.println("myCircle1 radius is "+myCircle1.getRadius());
                   System.out.println("myCircle2 radius is "+myCircle2.getRadius());
                   System.out.println("myCircle1 area is "+myCircle1.area());
                   System.out.println("myCircle1 circumference is "+myCircle1.circumference());
                   System.out.println("myCircle2 radius is "+myCircle2.toString());
                   myCircle2.setRadius(7.3);
                   System.out.println("now myCircle2 radius is "+myCircle2.toString());
                   System.out.println("myCircle1 radius is "+myCircle1.getRadius());
                                              }

}