melon_ex.java

刘艺编著的java教程的课本习题加例题代码 很有用哦！

class Melon
{float weight;
 static float total_weight=0;
 static int total_number=0;
 public Melon(float w)
  {weight=w;
   total_weight=total_weight+weight;
   total_number=total_number+1;
   }
 public void reduce()
 {total_weight=total_weight-weight;
  total_number=total_number-1;
   }
}
public class Melon_ex
{public static void main(String args[])
 {Melon m1,m2;
  m1=new Melon(10);
  m2=new Melon(12);
  System.out.println("Total weight:  "+m1.total_weight);
  System.out.println("Total number:  "+Melon.total_number);
  m1.reduce();
  System.out.println("Total weight:  "+Melon.total_weight);
  System.out.println("Total number:  "+Melon.total_number);
  m2.reduce();
  System.out.println("Total weight:  "+Melon.total_weight);
  System.out.println("Total number:  "+Melon.total_number);
  }
}