语源科技BlogJava-331929879

继承类

小飞 — Tue, 16 Oct 2007 06:47:00 GMT

class Father
{
int age;
String name;
void eat()
{
System.out.println("吃馍！");
}
}
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();
}
}

小飞 2007-10-16 14:47 发表评论

复数运算

小飞 — Fri, 12 Oct 2007 01:13:00 GMT

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){// 当前复数与方法参数another相减；
  Complex r = new Complex();
  r.real = real - another.real;
  r.image = image - another.image;
  return r;
}

public Complex multi(Complex another){ //当前复数与方法参数another相乘（注意复数相乘）；
  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();
    }
}

小飞 2007-10-12 09:13 发表评论

一个继承类

小飞 — Thu, 11 Oct 2007 07:09:00 GMT

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();
}
}

小飞 2007-10-11 15:09 发表评论