Java程序设计实用教程 书中代码1.doc
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例2-1
Example2_1.java
public class Example2_1
{
public static void main(String args[])
{
Rect rectangle1,rectangle2; //声明2个对象
rectangle1 = new Rect(); //创建对象
rectangle2 = new Rect();
rectangle1.width=128;
rectangle1.height=69;
rectangle2.width=18.9;
rectangle2.height=59.8;
double area=rectangle1.getArea();
System.out.println(rectangle1的面积:+area);
area=rectangle2.getArea();
System.out.println(rectangle2的面积:+area);
}
}
例2-2
Circle.java
public class Circle
{
double radius; //圆的半径
double getArea()
{
return 3.1415926*radius;
}
}
Lader.java
public class Lader
{
double above; //梯形的上底
double bottom; //梯形的下底
double height; //梯形的高
double getArea()
{
return (above+bottom)*height/2;
}
}
MainClass.java
public class MainClass
{
public static void main(String args[])
{
Circle circle=new Circle();
circle.radius=100;
double area=circle.getArea();
System.out.println(圆的面积:+area);
Lader lader=new Lader();
lader.above=10;
lader.bottom=56;
lader.height=8.9;
area=lader.getArea();
System.out.println(梯形的面积:+area);
}
}
例2-3
Rectangle.java
public class Rectangle //Rectangle类
{
double width;
double height;
double getArea()
{
return width*height;
}
}
class Example2_3 //主类
{
public static void main(String args[])
{
Rectangle r;
r=new Rectangle();
r.width=1.819;
r.height=1.5;
double area=r.getArea();
System.out.println(矩形的面积:+area);
}
}
例2-4
Example2_4.java
public class Example2_4
{
public static void main (String args[ ])
{
char ch1=国,ch2=庆;
int p1=969,p2=12353;
System.out.println(ch1+在Unicode表中的位置:+(int)ch1);
System.out.println(ch2+在Unicode表中的位置:+(int)ch2);
System.out.println(第+p1+个位置上的字符是:+(char)p1);
System.out.println(第+p2+个位
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