求圆的面积的java程序4-1,4-3
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);
}
}
4-3
class Lader{
double above,bottom,height;
Lader(){}
Lader(double a,double b,double h){
above=a;
bottom=b;
height=h;
}
public void setAbove(double a){
above=a;
}
public void setBottom(double b){
bottom=b;
}
public void setHeight(double h){
height=h;
}
double computeArea(){
return(above+bottom)*height/2.0;
}
}
public class Example4_1{
public static void main(String args[]){
double areal=0,area2=0;
Lader laderOne,laderTow;
laderOne=new Lader();
laderTow=new Lader(10,88,20);
laderOne.setAbove(16);
laderOne.setBottom(26);
laderOne.setHeight(100);
laderTow.setAbove(300);
laderTow.setBottom(500);
areal=laderOne.computeArea();
area2=laderTow.computeArea();
System.out.println("laderOne的above,bottom和height:"+laderOne.above+","+laderOne.bottom+","+laderOne.height);
System.out.println("laderOne的面积:"+areal);
System.out.println("laderTow的above,bottom和height:"+laderTow.above+","+laderTow.bottom+","+laderTow.height);
System.out.println("laderTow的面积:"+area2);
}
}