面向对象（上）类封装举例

import java.util.Scanner;

//—————小汽车类

class Engine{}

class Door{}

class Windows{}

class car{

String pinpai;

float price;

Engine eg1;

Door d[];

Windows w[];

void stop(){}

void start(){}

}

//——————长方形类

class Rectangle {

float len;

float width;

public float area(float len,float width){

return len*width;

}

public float circle(float len,float w){

return 2*(len+width);

}

}

public class Test{ // 主类，引用并测试与矩形之间的关系

Rectangle r1=new Rectangle();

public static void main(String args[]){

Test t1=new Test();

Scanner sc=new Scanner(System.in);

float len=0;

float width=0;

float s=0;

System.out.println("输入R1矩形的长是：");

len=sc.nextInt();

System.out.println("输入R1矩形的宽是：");

width=sc.nextInt();

s=t1.r1.area(len, width);

System.out.println("R1矩形的面积是："+s);

}

}