学生和教师类的实现

public void draw()

{

System.out.println(\此圆的半径r=\ }

public double getArea()

{

return PI*r*r; }

public double getCircumference()

{

return 2*PI*r; }

} /*class Eclipse implements shape { }*/

class Rectangle implements shape {

double length,width;

Rectangle(double a,double b) {

length=a; width=b;

}

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public {

void draw()

System.out.println(\ }

public double getArea()

{

return length*width; }

public double getCircumference()

{

return 2*(length+width); }

} class Triangle implements shape { double side1,side2,side3;

Triangle(double a,double b,double c) {

side1=a; side2=b; side3=c;

}

public void draw()

{

System.out.println(\

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}

public double getArea() {

double area,s;

s=(side1+side2+side3)/2;

area=Math.sqrt(s*(s-side1)*(s-side2)*(s-side3)); return area; }

public double getCircumference()

{

return(side1+side2+side3); }

} public class Testshape { public static void main(String[] args) {

Circle c=new Circle(2.0);

Rectangle r=new Rectangle(10.0,12.0); Triangle t=new Triangle(10,20,30);

c.draw();

System.out.println(\ r.draw();

System.out.println(\

t.draw();

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}

System.out.println(\}

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