JAVA
class b1
{
double r;
void setRadius(double a)
{
r=a;
}
double circumference()
{
return Math.PI*2*r;
}
double area()
{
return Math.PI*Math.pow(r,2);
}
}
class square
{
double a;
void setedge(double i)
{
a=i;
}
double circumference()
{
return a*4;
}
double area()
{
return a*a;
}
}
class rectangle
{
double length;
double width;
void setlw(double l,double w)
{
length=l;
width=w;
}
double circumference()
{
return 2*(length+width);
}
double area()
{
return length*width;
}
}
public class a1
{
public static void main (String[] args)
{
o1 c=new o1();
c.setRadius(10);
System.out.println("面積="+c.area()+"周長="+c.circumference());
square s1=new square();
s1.setedge(10);
System.out.println("面積="+s1.area()+"周長="+s1.circumference());
rectangle r1=new rectangle();
r1.setlw(10,5);
System.out.println("面積="+r1.area()+"周長="+r1.circumference());
}
}














