共回答了12个问题采纳率：91.7%

代码如下。输入参数和计算结果都为整数。具体类型请自行修改。import java.util.Scanner;

public class Test {

public static void main(String [] args){

while(true){

Shape shape = showMenu();

System.out.println("所选图形的周长为："+shape.getRound());

System.out.println("所选图形的面积为："+shape.getArea());

shape = null;

}

}

public static Shape showMenu(){

Shape shape = null;

System.out.println("请选择图形：");

System.out.println("1 圆2 矩形3 三角形9 退出");

int option = Shape.getInput();

switch (option) {

case 1:

shape = new Circle();

break;

case 2:

shape = new Rectangle();

break;

case 3:

shape = new Triangle();

break;

case 9:

System.out.println("系统退出！");

System.exit(0);

break;

default:

System.out.println("选项不存在");

shape = showMenu();

break;

}

return shape;

}

}

abstract class Shape{

/**

* 给图形的参数赋值。

* @param sc

*/

abstract void getParam();

/**

* 获取周长

* @return

*/

abstract int getRound();

/**

* 获取面积

* @return

*/

abstract int getArea();

/**

* 获取输入的参数

* @param sc

* @return

*/

public static int getInput(){

int x = Integer.MIN_VALUE;

try{

x = new Scanner(System.in).nextInt();

if(x < 0){

throw new Exception();

}

} catch (Exception e){

System.out.println("输入错误，请重新输入");

x = getInput();

}

return x;

}

}

//矩形

class Rectangle extends Shape{

private int side1;

private int side2;

public Rectangle(){

getParam();

}

void getParam(){

System.out.println("第一条边：");

this.side1 =getInput();

System.out.println("第二条边：");

this.side2 =getInput();

};

int getRound(){

return 2*(side1+side2);

}

int getArea(){

return side1*side2;

}

}

//圆形

class Circle extends Shape{

private int r;

public Circle(){

getParam();

}

void getParam(){

System.out.println("请输入半径：");

this .r = getInput();

}

int getRound(){

return (int) (2*Math.PI*r);

}

int getArea(){

return (int) (Math.PI*r*r);

}

}

//三角形

class Triangle extends Shape{

private int side1;

private int side2;

private int side3;

public Triangle(){

getParam();

}

void getParam(){

System.out.println("第一条边：");

this.side1 = getInput();

System.out.println("第二条边：");

this.side2 = getInput();

System.out.println("第三条边：");

this.side3 = getInput();

if(!isTriangle()){

System.out.println("无法构成三角形，请重新输入");

getParam();

}

}

int getRound(){

return side1+side2+side3;

}

int getArea(){

System.out.println("三角形面积计算稍显复杂，请自行写代码。");

return 0;

}

private boolean isTriangle(){ //根据两边之和大于第三边判断是否能构成三角形

return side1+side2>side3&&side1+side3>side2&&side2+side3>side1;

}

}

1年前

8