331929879

繼承類

class Father
{
 int age;
 String name;
 void eat()
 {
  System.out.println("吃饃！");
 }
}
class Son extends Father
{
 int height;
 void eat()
 {
  super.eat();
  System.out.println("喝酒");
 }
}
class Ex
{
 public static void main(String args[])
 {
  Son p=new Son();
  Father p1=new Son();
  p1.eat();
  p.eat();
 }
}

posted @ 2007-10-16 14:47 小飛 閱讀(162) | 評論 (0) | 編輯 收藏

復數運算

class Complex{
 double real;
    double image;

    public Complex add(Complex another){
  Complex res = new Complex();
  res.real = real + another.real;
  res.image = image + another.image;
  return res;
    }
    
 public Complex minus(Complex another){// 當前復數與方法參數another相減；
  Complex r = new Complex();
  r.real = real - another.real;
  r.image = image - another.image;
  return r;
 }
 
 public Complex multi(Complex another){ //當前復數與方法參數another相乘（注意復數相乘）； 
  Complex r = new Complex();
  r.real = real * another.real - image * another.image;
  r.image = real * another.image + image * another.real ;
  return r;
 }
 
 public void disp(){
  if( image == 0 ){
   System.out.print(real);
  }
  else
  {
   System.out.print(real + " + " + image + "i");
  }
 }
 
 public Complex(double real , double image){
  this.real = real;
  this.image = image ;
 }
 public Complex(){
  this(0 , 0);
 }
 
 public static void main (String[] args) {
  Complex c1 = new Complex(2 , 3);
  Complex c2 = new Complex(5 , 4);
  Complex res;
  
  c1.disp();
  System.out.print("  +   ");
  c2.disp();
  System.out.print("  =   ");
  c1.add(c2).disp();
  System.out.println();
  
  c1.disp();
  System.out.print("  -   ");
  c2.disp();
  System.out.print("  =   ");
  c1.minus(c2).disp();
  System.out.println();
  
  
  c1.disp();
  System.out.print("  *   ");
  c2.disp();
  System.out.print("  =   ");
  c1.multi(c2).disp();
  System.out.println();
    }
}

posted @ 2007-10-12 09:13 小飛 閱讀(279) | 評論 (0) | 編輯 收藏

一個繼承類

class Circle
{
 int r;
 static double PI=3.14;
 public int GetR(int r)
 {
  this.r=r;
  return r;
 }
 public void GetZ()
 {
  System.out.println(2*PI*r);
 }
 public void GetArea()
 {
  System.out.println(PI*r*r);
 }
}
class Cylinder extends Circle
{
 int height;
 public void GetCylinder(int r,int height)
 {
  this.r=r;
  this.height=height;
 }
 public void GetZ()
 {
  System.out.println(PI*r*r*height);
 }
 public void GetArea()
 {
  System.out.println(2*PI*r*r+2*PI*height);
 }
}
class Ex
{
 public static void main(String args[])
 {
  Circle p=new Circle();
  System.out.println( p.GetR(2));
  p.GetZ();
  p.GetArea();
  Cylinder p1=new Cylinder();
  p1.GetZ();
 }
}

posted @ 2007-10-11 15:09 小飛 閱讀(179) | 評論 (0) | 編輯 收藏