例4-1
public class ComputerCircleArea {
public static void main (String args[ ]){ double radius; double area; radius=163.16;
area=3.14*radius*radius;
System.out.printf(\半径是%5.3f的圆的面积:\\n%5.3f\\n\,radius,area); } }
例4-2
class Circle{ }
public class Example4_2 {
public static void main(String[] args) {
// TODO Auto-generated method stub double radius; double getArea(){ }
double area=3.14*radius*radius; return area;
Circle circle; circle=new Circle(); circle.radius=163.16;
double area=circle.getArea();
System.out.printf(\半径是%5.3f的圆的面积:\\n%5.3f\\n\,circle.radius,area); }
}
例4-3 class Lader{
double above,bottom,height;
}
Lader(){}
Lader(double a,double b,double h){ }
public void setAbove(double a){ }
public void setBottom(double b){ }
public void setHeight(double h){ }
double computerAera(){ }
return (above+bottom)*height/2.0; height=h; bottom=b; above=a; above=a; bottom=b; height=h;
public class Example4_1 {
public static void main(String[] args) {
// TODO Auto-generated method stub double area1=0,area2=0; Lader laderOne,laderTwo; laderOne=new Lader();
laderTwo=new Lader(10,88,20); laderOne.setAbove(16); laderOne.setBottom(26); laderOne.setHeight(100); laderTwo.setAbove(300); laderTwo.setBottom(500); area1=laderOne.computerAera(); area2=laderTwo.computerAera();
System.out.println(\的above,bottom和height:\ System.out.println(\的面积：\+area1); System.out.println(\的above,bottom和System.out.println(\的面积:\+area2);
+laderOne.above+\+laderOne.bottom+\+laderOne.height);
height:\+laderTwo.above+\+laderTwo.bottom+\+laderTwo.height);
}
}
System.exit(0);
例4-4 class Lader{ }
public class Example4_4 {
public static void main(String[] args) {
// TODO Auto-generated method stub Lader.bottom=60;
Lader laderOne,laderTwo;
System.out.println(\现在所有Lader对象的bottom都是\+Lader.bottom); laderOne=new Lader(); laderTwo=new Lader();
System.out.println(\的bottom:\+laderOne.getBottom()); System.out.println(\的bottom:\+laderTwo.getBottom()); laderOne.setAbove(11); laderTwo.setAbove(22); double above,height; static double bottom; void setAbove(double a){ }
void setBottom(double b){ }
double getAbove(){ }
double getBottom(){ }
return bottom; return above; bottom=b; above=a;