设计Shape类，Circle类，Retangle类，等求不同形状面积和周长，并排序

言曌 2017年04月26日22:54:17 1 3379 views

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主要考察：Java的继承和重写的知识

没有排序功能的代码如下：

package com.liuyanzhao;
class Shape {
String name;
public String getName() {
return name;
}
public double getArea() {//面积
return 0;
}
public double getGirth() {//周长
return 0;
}
}
class Square extends Shape {//正方形
double a;
public Square(double a) {
this.name = "正方形";
this.a = a;
}
public double getArea() {
return a*a;
}
public double getGirth() {
return 4*a;
}
}
class Rectangle extends Shape { //长方形
double a,b;
public Rectangle(double a,double b) {
this.name = "长方形";
this.a = a;
this.b = b;
}
public double getArea() {
return a*b;
}
public double getGirth() {
return (a+b)*2;
}
}
class Triangle extends Shape { //三角形
double a,b,c;
public Triangle(double a,double b,double c) {
this.name = "三角形";
this.a = a;
this.b = b;
this.c = c;
}
public double getArea() {
double p = (a+b+c)/2;
double s = (double)Math.sqrt(p*(p-a)*(p-b)*(p-c));
return s;
}
public double getGirth() {
return (a+b+c);
}
}
class Circle extends Shape { //圆
public static final double PI = 3.14;
double r;
public Circle(double r) {
this.name = "圆";
this.r = r;
}
public double getArea() {
return (double)(PI*r*r);
}
public double getGirth() {
return 2*PI*r;
}
}
public class Demo {
public static void main(String[] args) {
Shape []s = {new Square(3),new Rectangle(3, 4),new Triangle(3, 4, 5),new Circle(3)};
for(int i = 0;i<s.length;i++) {
System.out.println(s[i].getName()+",面积="+s[i].getArea()+",周长="+s[i].getGirth());
}
}
}

运行结果：

注意： 1、Squale，Circle，Retcangle，Triangle等类的方法不要传参 2、子类对父类的方法的重写，保持一致（是否传参，返回类型） 3、不要为了少写一个方法盲目继承，继承之间必须有附属（父子）关系同时我们再加一个功能，根据面积和周长大小进行排序

加排序功能代码如下：

package com.liuyanzhao;
class Shape {
String name;
public String getName() {
return name;
}
public double getArea() {//面积
return 0;
}
public double getGirth() {//周长
return 0;
}
public void compareArea(Shape []ss,int len) //根据面积大小升序排序
{
Shape s;
int i,j;
for(i=0;i<len;i++)
{
for(j=i+1;j<len;j++)
{
if(ss[j].getArea()<ss[i].getArea())
{
s=ss[i];
ss[i]=ss[j];
ss[j]=s;
}
}
}
}
public void compareGirth(Shape []ss,int len) //根据周长大小升序排序
{
Shape s;
int i,j;
for(i=0;i<len;i++)
{
for(j=i+1;j<len;j++)
{
if(ss[j].getGirth()<ss[i].getGirth())
{
s=ss[i];
ss[i]=ss[j];
ss[j]=s;
}
}
}
}
}
class Square extends Shape {//正方形
double a;
public Square(double a) {
this.name = "正方形";
this.a = a;
}
public double getArea() {
return a*a;
}
public double getGirth() {
return 4*a;
}
}
class Rectangle extends Shape { //长方形
double a,b;
public Rectangle(double a,double b) {
this.name = "长方形";
this.a = a;
this.b = b;
}
public double getArea() {
return a*b;
}
public double getGirth() {
return (a+b)*2;
}
}
class Triangle extends Shape { //三角形
double a,b,c;
public Triangle(double a,double b,double c) {
this.name = "三角形";
this.a = a;
this.b = b;
this.c = c;
}
public double getArea() {
double p = (a+b+c)/2;
double s = (double)Math.sqrt(p*(p-a)*(p-b)*(p-c));
return s;
}
public double getGirth() {
return (a+b+c);
}
}
class Circle extends Shape { //圆
public static final double PI = 3.14;
double r;
public Circle(double r) {
this.name = "圆";
this.r = r;
}
public double getArea() {
return (double)(PI*r*r);
}
public double getGirth() {
return 2*PI*r;
}
}
public class Demo {
public static void main(String[] args) {
Shape []s = {new Square(3),new Rectangle(3, 4),new Triangle(3, 4, 5),new Circle(2)};
for(int i = 0;i<s.length;i++) {
System.out.println(s[i].getName()+",面积="+s[i].getArea()+",周长="+s[i].getGirth());
}
System.out.println("-------------------------------------");
System.out.println("根据面积大小排序：");
new Shape().compareArea(s,s.length);
for(int i = 0;i<s.length;i++) {
System.out.println(s[i].getName()+",面积="+s[i].getArea()+",周长="+s[i].getGirth());
}
System.out.println("-------------------------------------");
System.out.println("根据周长大小排序：");
new Shape().compareGirth(s,s.length);
for(int i = 0;i<s.length;i++) {
System.out.println(s[i].getName()+",面积="+s[i].getArea()+",周长="+s[i].getGirth());
}
}
}