同步课 / 2016级 JavaSE（智能设备1班）

任务已更新

package org.edu2act.figure;
public abstract class Shape {
	public abstract void area() ;
	public abstract void perimeter();
}

package org.edu2act.figure;

public class Circle extends Shape{
             private double r;
             public Circle() {}
             public Circle(double R) {
            	 if(R<0){
            		 System.out.println("非法的输入");
            	 }
            	 else{
            		 r=R;
            	 }
             }
             public void area() {
            	 System.out.println("圆的面积为："+3.14*r*r);
             }
             public void perimeter() {
            	 System.out.println("圆的周长为："+2*3.14*r);
             }
             
}

package org.edu2act.figure;

public class Rectangle extends Shape{
           private double l;
           private double d;
           public Rectangle() {}
           public Rectangle(double l,double d) {
        	   if(l<0 || d<0) {
        		   System.out.println("非法的输入);
        	   }
        	   else{
        		  this.l=l;
        		  this.d=d;
        	   }
           }
           public void area() {
        	   System.out.println("长方形的面积为："+l*d);
           }
           public void perimeter() {
        	   System.out.println("长方形的周长为："+(l+l+d+d));
           }
}

package org.edu2act.figure;

public class Triangle extends Shape {
        private double a;
        private double b;
        private double c;
        public Triangle() {}
        public Triangle(double a,double b,double c) {
           if(a+b<=c || a+c<=b || b+c<=a || a<0 || b<0 || c<0) {
           System.out.println("非法的输入");
           }
           else {
        	   this.a=a;
        	   this.b=b;
        	   this.c=c;
           }
        }
        public void area() {
        	double s=(a+b+c)/2;
        	double S=Math.sqrt(s*(s-a)*(s-b)*(s-c));
        	System.out.println("三角形的面积为："+S);
        }
        public void perimeter() {
        	System.out.println("三角形的周长为："+(a+b+c));
        }
}

package org.edu2act.figure;
public class ShapeText {
	 interface distance{
		 double getDistance();
	 }
	 public static void main(String[] args) {
		 Circle m=new Circle(4.0);
		 Triangle M=new Triangle(3.0,4.0,5.0);
		 Rectangle N=new Rectangle(3.0,4.0);
		 m.area();
		 M.area();
		 N.area();
		 m.perimeter();
		 M.perimeter();
		 N.perimeter();
	 }
}