第7次作业--访问权限、对象使用

题目一

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。

Rect 类

package com.tomotoes.probleam.seven;

/**
 * @author Simon
 * @project practice
 * @package com.tomotoes.probleam
 * @date 2019/9/18 17:42
 */

public class Rect {
	double length;
	double width;
	double perimeter;
	double area;

	Rect(double length, double width) {
		this.length = length;
		this.width = width;
		this.perimeter = (length + width) * 2;
		this.area = length * width;
	}

	public double getPerimeter() {
		return perimeter;
	}

	public double getArea() {
		return area;
	}
}

Column 类

package com.tomotoes.probleam.seven;

/**
 * @author Simon
 * @project practice
 * @package com.tomotoes.probleam.seven
 * @date 2019/9/20 16:49
 */
public class Column {
	public Rect rect;
	public double height;
	public double volume;

	public Column(Rect rect, double height) {
		this.rect = rect;
		this.height = height;
		this.volume = this.rect.getArea() * height;
	}

	public double getVolume() {
		return this.volume;
	}

	public void setRect(Rect rect) {
		this.rect = rect;
		this.volume = this.rect.getArea() * height;
	}
}

主类

package com.tomotoes.probleam.seven;

import java.util.Scanner;

/**
 * @author Simon
 * @project practice
 * @package com.tomotoes.probleam.seven
 * @date 2019/9/20 16:46
 */
public class One {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		final double length = scanner.nextDouble();
		final double width = scanner.nextDouble();
		final double height = scanner.nextDouble();
		if (length <= 0 || width <= 0 || height <= 0) {
			throw new Error("Digital input must be positive.");
		}

		Column column = new Column(new Rect(length, width), height);
		final double volume = column.getVolume();
		System.out.println(volume);

		final double newLength = scanner.nextDouble();
		final double newWidth = scanner.nextDouble();
		final double newHeight = scanner.nextDouble();
		if (newLength <= 0 || newWidth <= 0 || newHeight <= 0) {
			throw new Error("Digital input must be positive.");
		}
		column.setRect(new Rect(newLength, newWidth));
		final double newVolume = column.getVolume();
		System.out.println(newVolume);
	}
}

运行结果

题目二

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

MyInteger 类

package com.tomotoes.probleam.seven;

/**
 * @author Simon
 * @project practice
 * @package com.tomotoes.probleam.seven
 * @date 2019/9/20 17:47
 */
public class MyInteger {
	private int value;

	public MyInteger(int value) {
		this.value = value;
	}

	public int getValue() {
		return value;
	}

	public void setValue(int value) {
		this.value = value;
	}

	public boolean isEven() {
		return this.value % 2 == 0;
	}
	public boolean isOdd() {
		return !isEven();
	}

	public static boolean isPrime(MyInteger i) {
		final int number = i.getValue();
		if (number < 2) {
			return false;
		}
		if (number == 2) {
			return true;
		}
		final int sqrt = (int) Math.sqrt(number);
		for (int j = 2; j <= sqrt; j++) {
			if (number % j == 0) {
				return false;
			}
		}
		return true;
	}
}

主类

package com.tomotoes.probleam.seven;

import java.util.Scanner;

/**
 * @author Simon
 * @project practice
 * @package com.tomotoes.probleam.seven
 * @date 2019/9/20 17:53
 */
public class Two {
	public static void main(String[] args) {
		System.out.println("Enter a negative number, exit the program.");

		Scanner scanner = new Scanner(System.in);

		while (true) {
			final int number = scanner.nextInt();
			if (number < 0) {
				return;
			}
			MyInteger myInteger = new MyInteger(number);
			System.out.println(MyInteger.isPrime(myInteger));
		}
	}
}

运行结果