* The Class PerimeterArea. This Class is to compute perimeter and area
*/
public class PerimeterArea {
/**
* The main method.
*
* @param args
* the arguments
*/
public static void main(String[] args) {
Shape TriangleObj = new Triangle(3, 4, 5);// 定義三邊為3,4,5的三角形
Shape RectangleObj = new Rectangle(5, 6);// 定義長為5，寬為6的矩形
Shape CircleObj = new Circle(5);// 定義半徑為5的對象
// 打印各個形狀的周長和面積
System.out.println(TriangleObj.toString());
System.out.println(RectangleObj.toString());
System.out.println(CircleObj.toString());
}
}
// 周長接口
interface perimeter {
public abstract double cutePerimeter();
}
// 面積接口
interface area {
public abstract double cuteArea();
}
// 抽象形狀類
abstract class Shape implements perimeter, area {
public abstract double cutePerimeter();
public abstract double cuteArea();
}
// 三角形
class Triangle extends Shape {
private int aSide;
private int bSide;
private int cSide;
public Triangle(){}
public Triangle(int aSide, int bSide, int cSide) {
this.aSide = aSide;
this.bSide = bSide;
this.cSide = cSide;
}
public double cutePerimeter() {
return aSide + bSide + cSide;
}
public double cuteArea() {
//面積公式
/*設三邊長分別為A、B、C，面積為S；周長的壹半P為（A+B+C）/2.
S=√[P（P-A）*（P-B）*（P-C）].
√為開二次方. */
int x = (aSide + bSide + cSide) / 2;
return Math.sqrt(x*(x-aSide)*(x-bSide)*(x-cSide));
}
public int getASide() {
return aSide;
}
public void setASide(int side) {
aSide = side;
}
public int getBSide() {
return bSide;
}
public void setBSide(int side) {
bSide = side;
}
public int getCSide() {
return cSide;
}
public void setCSide(int side) {
cSide = side;
}
public String toString() {
return "三角形的周長為:" + cutePerimeter() + "\n三角形的面積為:" + cuteArea() + "\n";
}
}
// 矩形
class Rectangle extends Shape {
private int longLength;
private int widthLength;
public Rectangle(){}
public Rectangle(int longLength, int widthLength) {
this.longLength = longLength;
this.widthLength = widthLength;
}
public double cutePerimeter() {
return 2 * (longLength + widthLength);
}
public double cuteArea() {
return longLength * widthLength;
}
public int getLongLength() {
return longLength;
}
public void setLongLength(int longLength) {
this.longLength = longLength;
}
public int getWidthLength() {
return widthLength;
}
public void setWidthLength(int widthLength) {
this.widthLength = widthLength;
}
public String toString() {
return "矩形的周長為:" + cutePerimeter() + "\n矩形的面積為:" + cuteArea() + "\n";
}
}
// 圓形
class Circle extends Shape {
public final double pi = 3.14;
private double radius;
public Circle(){}
public Circle(double radius) {
this.radius = radius;
}
public double cutePerimeter() {
return 2 * pi * radius;
}
public double cuteArea() {
return pi * radius * radius;
}
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}
public String toString() {
return "圓形的周長為:" + cutePerimeter() + "\n圓形的面積為:" + cuteArea() + "\n";
}
}
三角形面積已經修正~謝謝樓上的兄弟~set和get方法只是為了拓展性考慮~不局限於new才能設置參數值