访问权限、对象使用

题目1：在作业5的基础上，再创建一个柱体类，包含矩形对象、高和体积等三个成员变量，一个构造方法进行成员变量初始化，和计算体积、换底两个功能方法，在主类中输入长、宽、高，计算柱体体积，输入新的长、宽、高，创建新的矩形对象，并利用换底方法换底，再次计算柱体体积。

package Test;
public class test5 {
    int count;
    public static void main(String[] args) {
        // TODO Auto-generated method stub    
        //建立矩形的类的对象
        Rectangle rect = new Rectangle(2,3);
        double area = rect.getArea();
        double peri = rect.getPeri();
        //System.out.println("矩形的面积是："+area+"矩形的周长是："+peri);
        Pyramid pyr = new Pyramid(rect,4);
        double volumn = pyr.getVolumn();
        //System.out.println("四棱柱的体积是："+volumn);
        Podetium pode = new Podetium(rect,5);
        double volumn1 = pode.getVolumn();
        System.out.println("新柱体体积是："+volumn1);
    }
}
class  Rectangle{
    //矩形的宽
    private double width = 0.0;
    //矩形的高
    private double height = 0.0;
    //矩形的面积
    private double area = 0.0;
    //矩形的周长
    private double peri = 0.0;
    Rectangle(double width,double height){
        this.width = width;
        this.height = height;
    }
    //计算矩形的面积
    public double getArea() {
        area = width*height;
        return area;    
    }
    //计算矩形的周长
    public double getPeri() {
        peri = (height+width)*2;
        return peri;    
    }
    public double getWidth() {
        return width;
    }
    public void setWidth(double width) {
        this.width = width;
    }
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
}
class Pyramid{
    Rectangle rect;
    double height;
    double volumn;
    Pyramid(Rectangle rect,double height){
        this.rect = rect;
        this.height = height;
    }
    public double getVolumn() {
        volumn = rect.getArea()*height;
        return volumn;
    }
}
class Podetium{
    Rectangle rect;
    double height;
    double volumn;
    Podetium(Rectangle rect,double height){
        this.rect = rect;
        this.height = height;
    }
    public double getArea() {
        return rect.getHeight()*rect.getWidth();
    }
    public double getVolumn(){
        volumn = getArea()*height;
        return volumn;
    }
}

 

题目2：设计名为MyInteger的类，它包括： int型数据域value 一个构造方法，当指定int值时，创建MyInteger对象 数据域value的访问器和修改器 isEven( )和isOdd( )方法，如果当前对象是偶数或奇数，返回true 类方法isPrime(MyInteger i),判断指定的值是否为素数，返回true 在主类中创建MyInteger对象，验证MyInteger类中各方法。

 

package Test;

public class MyInteger {
	int value;
	public int getValue() {
		return value;
	}
	public void setValue(int value) {
		this.value = value;
	}
	MyInteger(int value){
		this.value = value;
	}
	public Boolean isEven(){
		return value%2==0;
	}
	public Boolean isOdd() {
		return value%2==1;
	}
	public static Boolean isPrime(MyInteger i) {
		Boolean flag = false;
		for(int j = 2;j<=i.value/2;j++) {
			if(i.value%j==0) 
				flag = true;
		}
		return flag;
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		MyInteger myinteger = new MyInteger(7);
		if(myinteger.getValue()<1) {
			try {
				throw new MyException("素数必须都大于1");
			} catch (MyException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}		
		//判断传入的值
		else if(MyInteger.isPrime(myinteger)) {
			System.out.println(myinteger.getValue()+"不是个素数");
		}
		else{
			System.out.println(myinteger.getValue()+"是个素数");
		}
	}
}
//自定义异常
class MyException extends Exception{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	MyException(String msg){
		//将信息传给父类构造函数
		super(msg);