java-7311练习(上)

Z时代
2024-01-10
分类：综合

java

java练习，仅供参考！

欢迎同学们交流讨论。

JDK 1.8 API帮助文档
JDK 1.6 API中文文档

Java GUI

-------------------------2016-10-23更新

HappyFace

package gui.test;
import javax.swing.JApplet;
import java.awt.Graphics;
public class HappyFace extends JApplet
{
    public void paint(Graphics canvas)
    {
        super.paint(canvas);
    	setSize(400,300);
        canvas.drawOval(100, 50, 200, 200);
        canvas.fillOval(155, 100, 10, 20);
        canvas.fillOval(230, 100, 10, 20);
        canvas.drawArc(150, 160, 100, 50, 180, 180);
    }
}

HappyFaceJFrame

package gui.test;
import java.awt.Graphics;
import javax.swing.JFrame;
public class HappyFaceJFrame extends JFrame
{
	public HappyFaceJFrame()
	{
		setSize(400,300);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
	}
    public void paint(Graphics canvas)
    {
        canvas.drawOval(100, 50, 200, 200);
        canvas.fillOval(155, 100, 10, 20);
        canvas.fillOval(230, 100, 10, 20);
        canvas.drawArc(150, 160, 100, 50, 180, 180);
    }
    public static void main(String[] args)
	{
    	HappyFaceJFrame guiwindow = new HappyFaceJFrame();
		guiwindow.setVisible(true);
	}
}

MultipleFaces

package gui.test;
import javax.swing.JApplet;
import java.awt.Graphics;
import java.awt.Color;
public class MultipleFaces extends JApplet
{
	public static final int FACE_DIAMETER = 50;
	public static final int X_FACE0 = 10;
	public static final int Y_FACE0 = 5;
	public static final int EYE_WIDTH = 5;
	public static final int EYE_HEIGHT = 10;
	public static final int X_RIGHT_EYE0 = 20;
	public static final int Y_RIGHT_EYE0 = 15;
	public static final int X_LEFT_EYE0 = 45;
	public static final int Y_LEFT_EYE0 = Y_RIGHT_EYE0;
	public static final int NOSE_DIAMETER = 5;
	public static final int X_NOSE0 = 32;
	public static final int Y_NOSE0 = 25;
	public static final int MOUTH_WIDTH = 30;
	public static final int MOUTH_HEIGHT0 = 0;
	public static final int X_MOUTH0 = 20;
	public static final int Y_MOUTH0 = 35;
	public static final int MOUTH_START_ANGLE = 180;
	public static final int MOUTH_EXTENT_ANGLE = 180;
	public void paint(Graphics canvas)
	{
		setSize(500, 300);
		int i, xOffset, yOffset; // Want i to exist after the loop ends
		for (i = 0; i <= 4; i++)
		{ 
			// Draw one face:
			xOffset = 50 * i;
			yOffset = 30 * i;
			// Draw face circle:
			if (i % 2 == 0) // if i is even
			{ 
				// Make face light gray
				//canvas.setColor(Color.LIGHT_GRAY);
				canvas.setColor(Color.YELLOW);
				canvas.fillOval(X_FACE0 + xOffset, Y_FACE0 + 30 * i, FACE_DIAMETER, FACE_DIAMETER);
			}
			canvas.setColor(Color.BLACK);
			canvas.drawOval(X_FACE0 + xOffset, Y_FACE0 + yOffset, FACE_DIAMETER, FACE_DIAMETER);
			// Draw eyes:
			canvas.setColor(Color.BLUE);
			canvas.fillOval(X_RIGHT_EYE0 + xOffset, Y_RIGHT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
			canvas.fillOval(X_LEFT_EYE0 + xOffset, Y_LEFT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
			// Draw nose:
			canvas.setColor(Color.BLACK);
			canvas.fillOval(X_NOSE0 + xOffset, Y_NOSE0 + yOffset, NOSE_DIAMETER, NOSE_DIAMETER);
			// Draw mouth:
			canvas.setColor(Color.RED);
			canvas.drawArc(X_MOUTH0 + xOffset, Y_MOUTH0 + yOffset, MOUTH_WIDTH, MOUTH_HEIGHT0 + 3 * i,
					MOUTH_START_ANGLE, MOUTH_EXTENT_ANGLE);
		}
		// i is 5 when the previous loop ends
		xOffset = 50 * i;
		yOffset = 30 * i;
		// Draw kissing face:
		// Draw face outline:
		canvas.setColor(Color.BLACK);
		canvas.drawOval(X_FACE0 + xOffset, Y_FACE0 + yOffset, FACE_DIAMETER, FACE_DIAMETER);
		// Draw eyes:
		canvas.setColor(Color.BLUE);
		canvas.fillOval(X_RIGHT_EYE0 + xOffset, Y_RIGHT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
		canvas.fillOval(X_LEFT_EYE0 + xOffset, Y_LEFT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
		// Draw nose:
		canvas.setColor(Color.BLACK);
		canvas.fillOval(X_NOSE0 + xOffset, Y_NOSE0 + yOffset, NOSE_DIAMETER, NOSE_DIAMETER);
		// Draw mouth in shape of a kiss:
		canvas.setColor(Color.RED);
		canvas.fillOval(X_MOUTH0 + xOffset + 10, Y_MOUTH0 + yOffset, MOUTH_WIDTH - 20, MOUTH_WIDTH - 20);
		// Add text:
		canvas.drawString("Kiss, Kiss.", X_FACE0 + xOffset + FACE_DIAMETER, Y_FACE0 + yOffset);
		// Draw blushing face:
		i++;
		xOffset = 50 * i;
		yOffset = 30 * i;
		// Draw face circle:
		canvas.setColor(Color.LIGHT_GRAY);
		canvas.fillOval(X_FACE0 + xOffset, Y_FACE0 + yOffset, FACE_DIAMETER, FACE_DIAMETER);
		canvas.setColor(Color.BLACK);
		canvas.drawOval(X_FACE0 + xOffset, Y_FACE0 + yOffset, FACE_DIAMETER, FACE_DIAMETER);
		// Draw eyes:
		canvas.setColor(Color.BLACK);
		canvas.fillOval(X_RIGHT_EYE0 + xOffset, Y_RIGHT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
		canvas.fillOval(X_LEFT_EYE0 + xOffset, Y_LEFT_EYE0 + yOffset, EYE_WIDTH, EYE_HEIGHT);
		// Draw nose:
		canvas.setColor(Color.BLACK);
		canvas.fillOval(X_NOSE0 + xOffset, Y_NOSE0 + yOffset, NOSE_DIAMETER, NOSE_DIAMETER);
		// Draw mouth:
		canvas.setColor(Color.BLACK);
		canvas.drawArc(X_MOUTH0 + xOffset, Y_MOUTH0 + yOffset, MOUTH_WIDTH, MOUTH_HEIGHT0 + 3 * (i - 2),
				MOUTH_START_ANGLE, MOUTH_EXTENT_ANGLE);
		// Add text:
		canvas.drawString("Tee Hee.", X_FACE0 + xOffset + FACE_DIAMETER, Y_FACE0 + yOffset);
	}
}

week1

1.1 编写第一个程序，输出“Hello world!”

package week1;
/*任务1
 *程序描述：编写第一个程序，输出“Hello world!”。 
 */
public class Hello 
{
	public static void main(String[] args)
	{
		System.out.println("hello world!");
	}
}

hello world!

1.2 输出你的短期/长期目标

package week1;
/*任务2
 *程序描述：
 *编写程序，第一行输出你的姓名；之后空第一行；
 *第 三及五行 输出你的 短期/长期 目标。
 *输出如下：  
 *My name: *** 
 * 
 *My short-term objective:*****         
 *My long-term objective:***********  
 */
public class MyLifeGoals 
{
	public static void main(String[] args) 
	{
		System.out.println("My name:***\n");
		System.out.println("My short-term objective:*****");
		System.out.println("My long-term objective:***********");
	}
}

My name:*** My short-term objective:***** My long-term objective:***********

1.3 多行输出一个宽 12 个字符、高 10行的字符“J”

package week1;
/*
 * 任务3
 * 程序描述：通过在多行输出 J 来组成一个
 * 宽 12 个字符、高 10行  的字符“J”。 
 */
public class JLetter 
{
	public static void main(String[] args)
	{
		String str = "JAVA";
		//输出 1-2 行
		for (int i = 0; i < 2; i++)
		{
			for (int j = 0; j < 3; j++)
			{
				System.out.printf("%s", str);
			}
			System.out.println();
		}
		//输出 3-6 行
		for (int i = 0; i < 4; i++)
		{
			//占位符长度包含字符本身的长度；即 10 = 4+6
			System.out.printf("%10s\n",str);
		}
		//输出 7-8  行
		System.out.printf("%s%9s\n","J",str);
		System.out.printf("%s%8s\n","JA",str);
		//输出 9-10 行
		System.out.printf("%5s%s\n",str,str);
		System.out.printf("%6s%s\n",str,"JA");
	}
}

JAVAJAVAJAVA JAVAJAVAJAVA JAVA JAVA JAVA JAVA J JAVA JA JAVA JAVAJAVA JAVAJA

1.4 用户信息：姓名、年龄、期望工资及婚否

package week1;
import java.util.Scanner;
/*
 * 任务4
 * 程序描述： 
 * （1） 首先定义四个变量，用来存放用户的姓名、年龄、期望工资及婚否 
 * （2） 分别接收用户输入的姓名、年龄、工资及婚否 
 * （3） 将这些信息分四行输出。 
 * 输出： 
 * 请输入你的姓名：周星星
 * 请输入你的年龄：18
 * 请输入你期望的工资：25000.9
 * 你是否已婚（true代表已婚，false代表未婚）：false
 * 你的信息如下：
 * 姓名：周星星
 * 年龄：18
 * 期望的工资：25000.9
 * 婚姻状态：false
 */
public class UserInfo
{
	public static void main(String[] args)
	{
		String name;   //设置变量
		int age;
		float expected_salary;
		boolean matital_status;
		//从键盘接收数据  
		Scanner scan = new Scanner(System.in);
		System.out.print("请输入你的姓名：");
		name = scan.nextLine();
		System.out.print("请输入你的年龄：");
		age = scan.nextInt();
		System.out.print("请输入你期望的工资：");
		expected_salary = scan.nextFloat();
		System.out.print("你是否已婚（true代表已婚，false代表未婚）：");
		matital_status = scan.nextBoolean();
		scan.close();   // 关闭 Scanner 对象
		System.out.println("你的信息如下：");
		System.out.println("姓名：" + name);
		System.out.println("年龄：" + age);
		System.out.println("期望的工资：" + expected_salary);
		System.out.println("婚姻状态：" + matital_status);
	}
}

请输入你的姓名：周星星请输入你的年龄：18 请输入你期望的工资：25000.9 你是否已婚（true代表已婚，false代表未婚）：false 你的信息如下：姓名：周星星年龄：18 期望的工资：25000.9 婚姻状态：false

1.5 User 类： get()、set()

package week1;
/*
 * 任务5
 * 程序描述： 该实验的目标是生成 User 类。 
 * - 三个成员变量
 * 	姓名（name）：字符串类型
 * 	年龄（age）：整形
 * 	性别（gender）：整形
 * - 六个成员方法
 * getName(): String 
 * setName(): void 
 * getAge(): int 
 * setAge(): void 
 * getGender():int 
 * setGender():void 
 */
public class User
{
	private String name;
	private int age;
	private int gender;
	public String getName()
	{
		return name;
	}
	public void setName(String name)
	{
		this.name = name;
	}
	public int getAge()
	{
		return age;
	}
	public void setAge(int age)
	{
		this.age = age;
	}
	public int getGender()
	{
		return gender;
	}
	public void setGender(int gender)
	{
		this.gender = gender;
	}
}

week2

-------------------------2016-10-14更新

2.1 我的Java成绩

package week2;
import java.util.Scanner;
/*
 * 任务 1 
 *程序描述：
 *接收用户从键盘上输入的 3 项 Java 成绩：课堂活跃度（activity）、作业(homework)、 考试(exam)；
 *之后从键盘上接收用户输入的这三项在最终成绩中的比例，分别为 activityPercent 占 30%、
 *homeworkPercent 占 30%和 examPercent 占 40%。最终按比例计算最 终成绩并输出。  
 */
public class Score
{
	public static void main(String[] args)
	{
		int score_activity;
		int score_homework;
		int score_exam;
		float score_total;
		Scanner scan = new Scanner(System.in);
		System.out.println("以下是3项Java成绩，请按提示输入");
		System.out.print("请输入 课堂活跃度 成绩：");
		score_activity = scan.nextInt();
		System.out.print("请输入 作业 成绩：");
		score_homework = scan.nextInt();
		System.out.print("请输入 考试 成绩：");
		score_exam = scan.nextInt();
		scan.close();
		score_total = (float) 
				( score_activity * 0.3
				+ score_homework * 0.3
				+ score_exam * 0.4
				);
		System.out.println("你的总成绩为：" + score_total);
	}
}

以下是3项Java成绩，请按提示输入请输入课堂活跃度成绩：86 请输入作业成绩：91 请输入考试成绩：77 你的总成绩为：83.9

2.2 颠倒输出一个三位整数

package week2;
import java.util.Scanner;
/*
 * 任务 2 
 * 程序描述：
 * 接收用户输入的一个三位整数（假设用户一定会输入一个三位整数），将其如 123 的数位颠倒，输出 321。 
 */
public class ReverseNumber
{
	public static void main(String[] args)
	{
		//定义一个三位整数(number)的个位(unit)、十位(ten)、百位(hundred)
		int number, unit, ten, hundred;
		Scanner scan = new Scanner(System.in);
		System.out.print("请输入一个三位整数：");
		number = scan.nextInt();
		scan.close();
		unit = number%10;  //取个位
		ten = number%100/10;  //取十位
		hundred = number/100;  //取百位
		System.out.println("这个数逆向输出为：" + unit + ten + hundred);
	}
}

请输入一个三位整数：198 这个数逆向输出为：891

2.3 一元二次方程--根的判别式

程序描述：接收用户从键盘输入的 a、b、c 值，然后利用公式计算两个根的值。
输出如下：

Let $ ax^2 + bx + c = 0 (a \neq 0), \(

\) \Large x_1=\frac{-b + \sqrt{b^2-4ac}}{2a}, \(

\) \Large x_2=\frac{-b - \sqrt{b^2-4ac}}{2a}, $

when $ \Delta=b^2-4ac $ only one repeated root

when $ \Delta>0 $ two real roots

when $ \Delta<0 $ two real roots

package week2;
import java.util.Scanner;
/*
 * 任务3
 * 程序描述：
 * 接收用户从键盘输入的 a、b、c 值，然后利用公式计算两个根的值。 
 */
public class Quadratic
{
	/*
	 * 关于类Math（java.lang.Math）的2个函数：
	 * 1.sqrt(double a) 返回正确舍入的 double 值的正平方根
	 * 2.pow(double a, double b) 返回第一个参数的第二个参数次幂的值
	 * 更多可访问：http://docs.oracle.com/javase/8/docs/api/
	 */
	public static void main(String[] args)
	{
		double a,b,c;  //一元二次方程各项系数
		Scanner scan = new Scanner(System.in);
        System.out.print("Insert value for a: ");
        a = scan.nextDouble();
        System.out.print("Insert value for b: ");
        b = scan.nextDouble();
        System.out.print("Insert value for c: ");
        c = scan.nextDouble();
        scan.close();
        System.out.println("Let " + a + "x^2 + " +b+ "x + " + c + " = 0");
        double delta; //根与系数的判别式  delta = b^2 - 4ac
        delta = Math.pow(b, 2) - (4 * a * c);
        if (delta > 0 || delta == 0)
		{
			double answer1 = (-b + Math.sqrt(delta)) / (2 * a);
			double answer2 = (-b - Math.sqrt(delta)) / (2 * a);
			System.out.println("The values are: "  + answer1 + ", " + answer2);
		}else 
		{
			System.out.println("Answer contains imaginary numbers");
		}
	}
}

Insert value for a: 1 Insert value for b: 2 Insert value for c: 1 Let 1.0x^2 + 2.0x + 1.0 = 0 The values are: -1.0, -1.0

Insert value for a: 1 Insert value for b: 1 Insert value for c: -6 Let 1.0x^2 + 1.0x + -6.0 = 0 The values are: 2.0, -3.0

Insert value for a: 3 Insert value for b: 2 Insert value for c: 1 Let 3.0x^2 + 2.0x + 1.0 = 0 Answer contains imaginary numbers

2.4 猜随机整数

package week2;
import java.util.Scanner;
/*
 * 任务 4
 * 程序描述：
 * 编写程序，实现产生一个从 1-N（N 由用户从键盘输入）的随机数。
 * 用户猜测一 个数，判断该猜测是否正确，如果正确，则输出“你太有才啦！”，否则输出“抱歉啦”及该随机数。
 */
public class RandomNumber
{
	/*
	 * 随机数可以用java.util.Random。
	 * 本程序使用的java.lang.Math;
	 * Math.random() 返回带正号的 double 值，该值大于等于 0.0 且小于 1.0。
	 * 更多可访问：http://docs.oracle.com/javase/8/docs/api/
	 */
	public static void main(String[] args)
	{
		int random_number,num;
		Scanner scan = new Scanner(System.in);
		System.out.print("请输入范围为 1-N 的整数 的最大值(N)：");
		num = scan.nextInt();
		//随机一个 1-N 的整数
		random_number = (int) (Math.random()*num + 1);
		//System.out.println(random_number);
		System.out.print("请(猜测)输入这个随机整数：");
		num = scan.nextInt();
		scan.close();
		if (num == random_number)
		{
			System.out.println("你太有才啦！");
		} else
		{
			System.out.println("抱歉啦,该随机数为：" + random_number);
		}
	}
}

请输入范围为 1-N 的整数 的最大值(N)：1
请(猜测)输入这个随机整数：1
你太有才啦！

请输入范围为 1-N 的整数 的最大值(N)：20
请(猜测)输入这个随机整数：11
抱歉啦,该随机数为：5

2.5 UserApp

package week2;
import week1.User;
import java.util.Scanner;
/*
 * 任务5
 * 程序描述：使用week1中生成的 User.java 类。
 * （一）获得用户输入的姓名、年龄及性别 
 * （1）声明三个变量：姓名（name：字符串类型）、年龄（age：整型）及性别（gender： 整型） 
 * （2） 接收用户输入的 name、age、gender 的值 
 * （3） 分三行输出这三个变量  
 * （二）转换年龄 
 * （1） 计算并将用户已经存在于世的分钟数（分钟=年龄×525600） 
 * （2） 计算用户年龄对应的世纪值（年龄/100） 
 * （三） 输出最大心率值
 *  增加 if-else 语句来计算输出男、女对应的不同的最大心率：
 *  男性的最大心率为 214-(0.8* 年龄)；女性的最大心率为 209-(0.7*年龄)。
 */
public class UserApp
{
	public static void main(String[] args)
	{
		//5.1.1 声明三个变量
		String name;
		int age;
		int gender;
		User user = new User();  //实例化一个对象
		Scanner scan = new Scanner(System.in);
		//5.1.2 输入；初始化变量
		System.out.print("Enter your name：");
		name = scan.nextLine();
		System.out.print("Enter your age in years：");
		age = scan.nextInt();
		System.out.print("Enter your gender(1 for female,0 for male)：");
		gender = scan.nextInt();
		scan.close();
		user.setName(name);
		user.setAge(age);
		user.setGender(gender);
		//5.1.3 输出结果
		System.out.println("Your name：" + user.getName());
		System.out.println("Your age in years：" + user.getAge());
		System.out.println("Your gender：" + gender);
		//5.2 转换年龄 
		long minutes = age * 525600;
		float centuries = (float) (age / 100.0); 
		//5.2.1 输出用户已经存在于世的分钟数（分钟=年龄×525600） 
		System.out.println("\tYour age in minutes is " + minutes + " minutes.");
		//5.2.2 输出用户年龄对应的世纪值（年龄/100） 
		System.out.println("\tYour age in centuries is " + centuries + " centuries.");
		//5.3  输出最大心率值 ;男性的最大心率为 214-(0.8* 年龄)；女性的最大心率为 209-(0.7*年龄)。
		// 条件运算符(三元运算符) 判断 计算心率
		double heart_rate = 0==user.getGender() ? 214-(0.8*age):209-(0.7*age);
		System.out.println("Your max heart rate is " + heart_rate + " beats per minutes.");
	}
}

Enter your name：Lucie Enter your age in years：25 Enter your gender(1 for female,0 for male)：1 Your name：Lucie Your age in years：25 Your gender：1 Your age in minutes is 13140000 minutes. Your age in centuries is 0.25 centuries. Your max heart rate is 191.5 beats per minutes.

Enter your name：Kao Enter your age in years：19 Enter your gender(1 for female,0 for male)：0 Your name：Kao Your age in years：19 Your gender：0 Your age in minutes is 9986400 minutes. Your age in centuries is 0.19 centuries. Your max heart rate is 198.8 beats per minutes.

week3

-------------------------2016-10-25更新

3.1 计算 1~15 所有不能被 2或者3 整除的和

package week3;
/*
 * 任务 1
 * 程序描述 ：计算从1-15中所有不能被 2或者3 整除的数值 和
 */
public class Sum 
{
	public static void main(String []args)
	{
		int digit;
		int sum=0;
		for (digit = 1; digit <= 15; ++digit)
		{
			//既不能被3整除，也不能被2整除
			if(digit%3!=0 && digit%2!=0)
			{
				sum+=digit;
				//System.out.println(digit);
			}
		}
		System.out.println("sum = " + sum);
	}
}

sum = 37

3.2 “你要继续玩吗（输入yes 或 not ）： ”

package week3;
import java.util.Scanner;
/*
 * 任务 2
 * 程序描述 ：首先 输出提示信息“你要继续玩吗（输入yes 或  not ）： ”
 * 接收用户输入的一行内容， 判断其首字符是否为 yes 或 not；
 * 如果用户输入的是  yes 或  not ，则退出循环输用户的选择，
 * 如果用户输入的不是 yes 或  not ，则输出提示并等待用户的输入。
 */
public class YesOrNo 
{
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		String answer;
		while (true)
		{
			System.out.print("Continue? (enter yes or not): ");
			answer = scan.nextLine();
			if (answer.equals("yes"))
			{
				System.out.println("\nThe selection was y for Yes.");
				break;
			}
			if (answer.equals("not"))
			{
				System.out.println("\nThe selection was n for No.");
				break;
			}
		}
		scan.close();
	}
}

Continue? (enter yes or not): hello
Continue? (enter yes or not): how are you?
Continue? (enter yes or not): hi
Continue? (enter yes or not): hehe
Continue? (enter yes or not): not
The selection was n for No.

Continue? (enter yes or not): what should I input?
Continue? (enter yes or not): yes
The selection was y for Yes.

3.3 猜数字

package week3;
import java.util.Random;
import java.util.Scanner;
/*
 * 任务 3：猜数
 * 程序描述 ：程序随机产生一个从 1-10 的整型随机数。用户多次输入猜测值：
 * 如果小于 5次 即猜中 ，输出“你聪明绝顶啦！”（或其他个性提示）加上猜中所用次数；
 * 如果猜测次数 >=5 且没有猜中，输出“呵你 outout 啦”（或其他个性提示）并附上随机数 ，退出循环；
 * 如果用户输入的整数小于1或大于10，则提示“ 无效输入，请重新输入：”，等待用户 输入有效的数值。
 */
public class Guess
{
	public static void main(String[] args)
	{
		Random rnd = new Random();        //创建一个新的随机数生成器
		/*rnd.nextInt(10):生成[0,10)区间的整数*/
		int randomNumber = rnd.nextInt(10)+1;  //1-10
		int guessCount = 0;    //猜数的次数
		int guessDigit;        //猜数的数字
		Scanner scan = new Scanner(System.in);
		do
		{
			System.out.print("请输入1-10内的整数: ");
			guessDigit = scan.nextInt();
			//输入的整数小于1或大于10，等待用户 输入有效的数值。
			while (guessDigit < 1 || guessDigit > 10)
			{
				System.out.println(guessDigit + " 为无效输入！");
				System.out.print("请输入1-10内的整数: ");
				guessDigit = scan.nextInt();
			}
			++guessCount;   //此时已经有效输入
			if (guessDigit == randomNumber)
			{
				System.out.println("恭喜你，猜对啦！你猜了"
						+ guessCount
						+ "次。");
				break;
			}
		} while (guessCount < 5);
		scan.close();
		if (guessCount == 5)
		{
			System.out.println("抱歉，猜错啦！你猜了5次。"
						+ "随机数为："
						+ randomNumber);
		}
	}
}

请输入1-10内的整数: 0 0 为无效输入！请输入1-10内的整数: 11 11 为无效输入！请输入1-10内的整数: 5 恭喜你，猜对啦！你猜了1次。

请输入1-10内的整数: 6 请输入1-10内的整数: 5 请输入1-10内的整数: 4 请输入1-10内的整数: 3 请输入1-10内的整数: 1 抱歉，猜错啦！你猜了5次。随机数为：8

3.4 整数的小运算

3.4.1 NumberOperations

package week3;
/*
 * 任务 4
 * 整数的运算
 */
public class NumberOperations
{
	private int number;
	//构造方法 ：对成员变量 number 赋值
	public NumberOperations(int numberIn) 
	{
		number = numberIn;
	}
	public int getNumber()
	{
		return number;
	}
	//返回所有 (0,number) 的奇数(以tab间隔）
	public String oddsUnder()
	{
		String oddNumbers = "\t";
		for (int i = 1; i < number; i++)
		{
			if (i%2 != 0)
			{
				oddNumbers += (i + "\t");
			}
		}
		return oddNumbers;
	}
	//返回 从 (1,number) 的    2的幂(平方)
	public String powersTwoUnder()
	{
		int powerNumber = 0; //2的幂(平方)
		String powerNumbers = "\t";
		for (int i = 0; i < number; i++)
		{
			powerNumber = (int)Math.pow(2, i);
			if (powerNumber >= number) break;
			powerNumbers += ( powerNumber + "\t");
		}
		return powerNumbers;
	}
	//与初始值比较大小，number 大,小,等-> 1,-1,0
	public int isGrater(int compareNumber)
	{
		if(number > compareNumber) return 1;
		else if(number < compareNumber) return -1;
		else return 0;
	}
}

3.4.2 NumberOpsDriver

package week3;
import java.util.Scanner;
/*
 * 任务 4
 * 测试整数的运算
 */
public class NumberOpsDriver 
{
	public static void main(String[] args)
	{
		int number;   //用户输入的整数
		Scanner scan = new Scanner(System.in); //准备接收键盘输入
		//（1）输入三个的正整数(以空格间隔，并以0结束)
		System.out.println("Enter a list of positive integers separated with a space followed by 0:");
		while (true)
		{
			number = scan.nextInt();  //从键盘读取一个int值
			if(number == 0) break;
			//（2）创建 NumberOperations对象，并分别调用函数
			NumberOperations numOps = new NumberOperations(number);
			System.out.println("For:  " + number);
			System.out.println("  Odds under:" + numOps.oddsUnder());
			System.out.println("  Powers of 2 under:" + numOps.powersTwoUnder());
			//有选择的输出  2个数值的大小比较
			if (numOps.isGrater(12) == 1)
				System.out.println("  Compare " + number + " > 12  :\t1");
			else if (numOps.isGrater(12) == -1)
				System.out.println("  Compare " + number + " < 12   :\t-1");
			else
				System.out.println("  Compare " + number + " = 12  :\t0");
		}
		scan.close();
	}
}

Enter a list of positive integers separated with a space followed by 0: 12 9 17 0 For: 12 Odds under: 1 3 5 7 9 11 Powers of 2 under: 1 2 4 8 Compare 12 = 12 : 0 For: 9 Odds under: 1 3 5 7 Powers of 2 under: 1 2 4 8 Compare 9 < 12 : -1 For: 17 Odds under: 1 3 5 7 9 11 13 15 Powers of 2 under: 1 2 4 8 16 Compare 17 > 12 : 1

week4

-------------------------2016-10-31更新

4.1 求三个整数的最小值（多种方法）

package week4;
import java.util.Scanner;
/*
 * 任务 4.1
 * 程序描述 ：求3个整数最小值
 */
public class Minor
{
	//0. 三个整数一定存在一个数 小于等于 另外两个数
    public int minFun0(int a, int b, int c)
    {
        int minNum;  //最小数的临时变量
        if (a <= b && a <= c )minNum = a;
        else if (b <= a && b <= c)minNum = b;
        else minNum = c;
        return minNum;
    }
    //1. if-else
    public int minFun1(int a, int b, int c)
    {
        int minNum;  //最小数的临时变量
        if (a < b)
        {
            if (a < c) minNum = a;
            else minNum = c;
        }
        else
        {
            if (b < c) minNum = b;
            else minNum = c;
        }
        return minNum;
    }
    //2. if-else
    public int minFun2(int a, int b, int c)
    {
        int minNum;  //最小数的临时变量
        if (a < b) minNum = a;
        else minNum = b;
        if (c < minNum) minNum = c;
        return minNum;
    }
    //3. 条件运算符 + 临时变量
    public int minFun3(int a, int b, int c)
    {
        int minNum;  //最小数的临时变量
        minNum = a<b ? a:b;
        minNum = minNum<c ? minNum:c;
        return minNum;
    }
    //4. 条件运算符 (同理，不同顺序即可)
    public int minFun4(int a, int b, int c)
    {
        return (a<b ? a:b)<c ? (a<b ? a:b):c;
    }
    //5. 条件运算符 (同理，不同顺序即可)
    public int minFun5(int a, int b, int c)
    {
        return a<b ? (a<c?a: c) : (b<c?b: c);
    }
    //6. 3个整数由小至大排序
    public int minFun6(int a, int b, int c)
    {
    	//如果为真，则（异或运算）交换位置
        if(a > b){ a ^= b;  b ^= a;  a ^= b; }
        if(a > c){ a ^= c;  c ^= a;  a ^= c; }
        if(b > c){ b ^= c;  c ^= b;  b ^= c; }
        return a;
    }
    //7. 两点坐标参数比较  + 条件运算符
    public int minFun7(int a, int b, int c)
    {
    	return ((a+b) - Math.abs(a-b))/2 < c 
    			? (a+b - Math.abs(a-b))/2 :c;
    }
    //8. 三点坐标参数比较
    public int minFun8(int a, int b, int c)
    {
    	return ((a+b - Math.abs(a-b))/2 + c 
    			- Math.abs(c-(a+b - Math.abs(a-b))/2))/2;
    }
    public static void main(String[] args)
    {
        int resNumber[] = new int[9];  //存放结果
        int num1, num2, num3;
        Scanner scan = new Scanner(System.in);
        System.out.println("Please input three integers:");
        num1 = scan.nextInt();
        num2 = scan.nextInt();
        num3 = scan.nextInt();
        scan.close();
        Minor minFuns = new Minor();
        resNumber[0] = minFuns.minFun0(num1, num2, num3);
        resNumber[1] = minFuns.minFun1(num1, num2, num3);
        resNumber[2] = minFuns.minFun2(num1, num2, num3);
        resNumber[3] = minFuns.minFun3(num1, num2, num3);
        resNumber[4] = minFuns.minFun4(num1, num2, num3);
        resNumber[5] = minFuns.minFun5(num1, num2, num3);
        resNumber[6] = minFuns.minFun6(num1, num2, num3);
        resNumber[7] = minFuns.minFun7(num1, num2, num3);
        resNumber[8] = minFuns.minFun8(num1, num2, num3);
        // 循环遍历输出结果
        for (int i = 0; i < resNumber.length; i++)
		{
			System.out.println("minFun" + (i+1) + ": " + resNumber[i]);
		}
    }
}

Please input three integers: 8 1 7 minFun1: 1 minFun2: 1 minFun3: 1 minFun4: 1 minFun5: 1 minFun6: 1 minFun7: 1 minFun8: 1 minFun9: 1

4.2 回文（字符串）测试

package week4;
import java.util.Scanner;
/*
 * 任务 4.2
 * 程序描述 ：进行回文测试，如字符串“abdba”为回文palindrome
 * （1）提示用户输入一个字符串
 * （2）如果字符串为回文，则输出“这是回文”，否则输出“不是回文哦”
 * （3）输出提示“要测试另一个字符串吗？ 如果用户输入了y或Y，则执行（2），否则退出程序
 */
public class PalindromeTester
{
	public static void main(String[] args)
	{
		String string = null;
		char index;   //输入的第一个字符
        Scanner scan = new Scanner(System.in);
        System.out.print("请输入一个字符串:");
        string = scan.nextLine();
        do
		{
			if (palindrome(string))
				System.out.println(string + " 是回文！");
			else
				System.out.println(string + " 不是回文哦。");
			System.out.println("\n要测试另一个字符串吗？");
			System.out.print("继续测试输入 y/Y，否则输入其他:");
			index = scan.nextLine().charAt(0);
			switch (index)
			{
			case 'y':
			case 'Y':
				System.out.print("请输入一个字符串:");
				string = scan.nextLine();
				break;
			case 'n':
			case 'N':
			default:
				System.out.print("程序结束！");
				break;
			}
		} while (index == 'y'|| index=='Y');
        scan.close();
	}
	private static boolean palindrome(String string)
	{
		boolean flag = true;  //默认返回真
		int len = string.length(); //字符串的长度
		for (int i = 0; i < len/2; i++)
		{
			if (string.charAt(i) != string.charAt(len-1-i))
			{
				flag = false;
				break;
			}
		}
		return flag;
	}
}

请输入一个字符串:test test 不是回文哦。要测试另一个字符串吗？继续测试输入 y/Y，否则输入其他:y 请输入一个字符串:aba aba 是回文！要测试另一个字符串吗？继续测试输入 y/Y，否则输入其他:n 程序结束！

4.3 判断小数点的两边有多少位

package week4;
import java.math.BigDecimal;
import java.util.Scanner;
/*
 ** 任务 4.3
 ** 程序描述 ：
 * （1）接收用户输入的一个double类型的数值
 * （2）判断该数值小数点左侧及右侧各有多少位
 * 
 ** 解题思路与方法局限：
 * 本程序 用户的输入是以Double类型为接收的，故也是基于double类型处理的；
 * a）digitalBitsFun1
 * 原理：Double.toString(doubleInput)将小数转化为字符串进行处理，查找'.'的位置进行判断。
 * 局限：问题就是小数转字符串时候会出现科学计数法，这样结果就错误，如“1.32456783E7 小数点左边有1位，右边有10位。”。
 * 改进：使用nextLine()接收用户输入，直接传字符串参数。
 * b）digitalBitsFun2
 * 原理：将一个浮点数进行数值运算，分离开整数部分和小数部分；整数部分通过"乘10取余"计算位数，小数部分通过"乘10舍整"计算位数。
 * 局限：计算机对于浮点数的存储（二进制）位数是有限制的，当精度过高时候会产生溢出导致结果不准确（错误）。
 * 改进：精度问题，统一使用高精度的存储方式。
 * 
 ** 给出一个测试结果，可以对比发现方法的局限性：
 * 请输入一个小数:123465789.123456789123
 * digitalBitsFun1:
 * 1.2346578912345679E8 小数点左边有1位，右边有18位。
 * digitalBitsFun2:
 * 1.2346578912345679E8 小数点左边有9位，右边有8位。
 * 
 ** 程序说明：
 * 本程序对于整数部分或小数部分长度为7以内的输入结果是正确的。至于局限性了解即可。
 * digitalBitsFun2中很可能出现精度问题导致结果的异常，而精度也决定了误差；
 * 经过很多次的调试发现还是要统一BigDecimal类型，比如BigDecimal构造函数参数为字符串（double+""）；
 * 在进行BigDecimal运算过程中 如果出现低精度的浮点数，就会影响结果，如new BigDecimal(doubleInput*10+"");
 * 
 */
public class DigitalTest
{
	public static void main(String[] args)
	{
		double doubleInput;
		Scanner scan = new Scanner(System.in);
		System.out.print("请输入一个小数: ");
        doubleInput = scan.nextDouble();
        scan.close();
        System.out.println("digitalBitsFun1:");
        digitalBitsFun1(doubleInput);
        System.out.println("digitalBitsFun2:");
        digitalBitsFun2(doubleInput);
	}
	private static void digitalBitsFun1(double doubleInput)
	{
		String doubleStr = Double.toString(doubleInput);
		int pointIndex = doubleStr.indexOf('.');
		System.out.println(doubleStr + " 小数点左边有"
				+ pointIndex + "位，右边有"
				+ (doubleStr.length() - pointIndex - 1 ) 
				+ "位。");
	}
	private static void digitalBitsFun2(double doubleInput)
	{
		double integer = Math.floor(doubleInput);  //取整数部分
		BigDecimal decimals ;  //小数部分
		int integerCount = 0;  //整数长度
		int decimalCount = 0;  //小数长度
		//取小数部分
		BigDecimal doubleIn = new BigDecimal(doubleInput+"");
		BigDecimal integerIn = new BigDecimal(integer + "");
		decimals = doubleIn.subtract(integerIn);
		//System.out.println("小数部分:" + decimals);
		//计算整数长度
		int i = 1; //临时步长
		if (integer == 0) integerCount++;
		else
		{
			while (integer != integer% i)
			{
				integerCount++;
				i *= 10;
			}
		}
		//计算小数长度
		BigDecimal j = new BigDecimal(10); //临时步长
		while (decimals.doubleValue() > 0)
		{
			decimalCount++;
			BigDecimal multiply10 = decimals.multiply(j);
			BigDecimal integerDeci = new BigDecimal(Math.floor(multiply10.doubleValue()));
			decimals = multiply10.subtract(integerDeci);
			//测试/调试输出
			/*System.out.println("1---" + multiply10);
			System.out.println("2---" + integerDeci);
			System.out.println("1-2 = " + decimals);*/
		}
		System.out.println(doubleInput 
				+ " 小数点左边有" + integerCount 
				+ "位，右边有" + decimalCount + "位。");
	}
}

请输入一个小数: 1234567.1234567 digitalBitsFun1: 1234567.1234567 小数点左边有7位，右边有7位。 digitalBitsFun2: 1234567.1234567 小数点左边有7位，右边有7位。

4.4 Dog项目

package week4;
/*
 * 任务 4.4.1
 * GoodDog类
 */
public class GoodDog
{
	private int size;
	GoodDog(int sizeIn)
	{
		size = sizeIn;
	}
	void bark()
	{
		if (size <= 14) System.out.println("Yip!Yip!");
		else if(size > 14 & size < 60) System.out.println("Ruff!Ruff!");
		else System.out.println("Wooof!Wooof!");
	}
	public int getSize()
	{
		return size;
	}
	public void setSize(int size)
	{
		this.size = size;
	}
}

package week4;
/*
 * 任务 4.4.2
 * 测试狗叫
 */
public class GoodDogTestDrive
{
	public static void main(String[] args)
	{
		GoodDog dog1 = new GoodDog(0);
		GoodDog dog2 = new GoodDog(0);
		GoodDog dog3 = new GoodDog(0);
		dog1.setSize(10);
		dog1.bark();
		dog2.setSize(50);
		dog2.bark();
		dog3.setSize(70);
		dog3.bark();
	}
}

Yip!Yip! Ruff!Ruff! Wooof!Wooof!

4.5 模拟掷骰子

package week4;
/*
 * 任务 4.5.1
 * Die类，模拟掷骰子。
 * 
 */
public class Die
{
	private int faceValue;
	public Die()
	{
		faceValue = 1;
	}
	public int roll()
	{
		return faceValue = (int)(Math.random()*6 + 1);
	}
	public String toString()
	{
		return Integer.toString(faceValue);
	}
	public int getFaceValue()
	{
		return faceValue;
	}
	public void setFaceValue(int faceValue)
	{
		this.faceValue = faceValue;
	}
}

package week4;
/*
 * 任务 4.5.2
 * RollingDice类，模拟掷骰子。
 * 
 */
public class RollingDice
{
	public static void main(String[] args)
	{
		int sum;  //
		Die die1;  //Die类引用变量die1
		Die die2;  //Die类引用变量die2
		//创建两个Die类的对象并赋值给die1,die2
		die1 = new Die();
		die2 = new Die();
		//调用两个对象的roll方法来模拟掷骰子
		die1.roll();
		die2.roll();
		//输出两个骰子的点数
		System.out.println("die1:" + die1.toString());
		System.out.println("die2:" + die2.toString());
		System.out.println();
		int i = die1.roll();  //调用die1的roll()并将返回值赋给int类型的变量i
		die2.setFaceValue(4);  //以4为实参调用die2的setFaceValue()
		//输出两个骰子的点数
		System.out.println("die1:" + i);
		System.out.println("die2:" + die2.toString());
		//调用die1、die2的getFaceValue()获得两个骰子的点数并求和，输出和
		sum = die1.getFaceValue() + die2.getFaceValue();
		System.out.println("sum= " + sum);
		System.out.println();
		//调用die1、die2的roll()并将和赋值给sum
		sum = die1.roll() + die2.roll();
		//输出两个骰子的点数以及点数和
		System.out.println("die1:" + die1.toString());
		System.out.println("die2:" + die2.toString());
		System.out.println("sum= " + sum);
	}
}

die1:3
die2:1
die1:1
die2:4
sum= 5
die1:6
die2:4
sum= 10

week5

-------------------------2016-11-07更新

5.1 UserInfo 、UserInfoDrive

5.1.1 UserInfo

package week5;
public class UserInfo
{
	private String firstName;
	private String lastName;
	private String location;
	private int age;
	private int status;
	private static final int OFFLINE = 0;  //用户离线
	private static final int ONLINE = 1;   //用户在线
	public UserInfo(String firstNameIn, String lastNameIn)
	{
		firstName = firstNameIn;
		lastName = lastNameIn;
		setLocation("Not specified");
		setAge(0);
		status = OFFLINE;
	}
	public String toString()
	{
		String output = "";
		String statusStr = null; //状态字符串
		if (status == 0) statusStr = "Offline";
		if (status == 1) statusStr = "Online";
		output = "Name: " + lastName
				+ " " + firstName
				+ "\nLocation: " + location
				+ "\nAge: " + age
				+ "\nStatus: " + statusStr ;
		return output;
	}
	public String getLocation()
	{
		return location;
	}
	public void setLocation(String locationIn)
	{
		this.location = locationIn;
	}
	public int getAge()
	{
		return age;
	}
	public boolean setAge(int ageIn)
	{
		age = ageIn;
		boolean flag;
		if (age > 0) flag = true;
		else flag = false;
		return flag;
	}
	public void logOff()
	{
		status = OFFLINE;
	}
	public void logOn()
	{
		status = ONLINE;
	}
	public static void main(String[] args)
	{
		UserInfo userInfo = new UserInfo("Jane", "Lane");
		System.out.println(userInfo.toString());
		System.out.println("-----------------------");
		userInfo.setAge(23);
		userInfo.setLocation("Auburn");
		userInfo.logOn();
		System.out.println(userInfo.toString());
	}
}

Name: Lane Jane Location: Not specified Age: 0 Status: Offline ----------------------- Name: Lane Jane Location: Auburn Age: 23 Status: Online

5.1.2 UserInfoDrive

package week5;
public class UserInfoDrive
{
	public static void main(String[] args)
	{
		UserInfo user1 = new UserInfo("Linda", "Jiang");
		System.out.println(user1.toString());
		System.out.println("-----------------------");
		user1.setLocation("Virginia");
		user1.setAge(20);
		user1.logOn();
		System.out.println(user1.toString());
		System.out.println("-----------------------");
		UserInfo user2 = new UserInfo("yi", "Jiang");
		System.out.println(user2.toString());
		System.out.println("-----------------------");
		user2.setLocation("Qingdao City");
		user2.setAge(22);
		user2.logOn();
		System.out.println(user2.toString());
	}
}

Name: Jiang Linda Location: Not specified Age: 0 Status: Offline ----------------------- Name: Jiang Linda Location: Virginia Age: 20 Status: Online ----------------------- Name: Jiang yi Location: Not specified Age: 0 Status: Offline ----------------------- Name: Jiang yi Location: Qingdao City Age: 22 Status: Online

5.2 模拟账户存取

5.2.1 Account

package week5;
public class Account
{
	private String acctNumber;  //银行帐号
	private String name;        //姓名
	private double balance;    //余额
	private static final double RATE = 0.035; //利息
	public Account(String acctNumber, String name, double balance)
	{
		this.acctNumber = acctNumber;
		this.name = name;
		this.balance = balance;
	}
	//存款
	public double deposit(double amount)
	{
		return balance += amount;
	}
	//取款
	public double withdraw(double amount)
	{
		return balance -= amount;
	}
	//加息
	public double addInterest()
	{
		return balance *= (1 + RATE);
	}
	public String toString()
	{
		//打印输入余额（四舍五入）保留2位小数
		double balanceT = (double)Math.round(balance*100)/100;
		String output = 
				  "AcctNumber: " + acctNumber
				+ "\n      Name: " + name
				+ "\n   Balance: " + balanceT + "\n";
		return output;
	}
}

5.2.2 AccountDrive

package week5;
public class AccountDrive
{
	public static void main(String[] args)
	{
		Account acct1 = new Account("60000001", "Alice", 222);
		Account acct2 = new Account("60000002", "Eric", 2222);
		Account acct3 = new Account("60000003", "Lia", 22222);
		acct1.deposit(300.00);   //acct1存款300
		acct2.deposit(500.00);   //acct2存款500
		acct2.withdraw(400.00);  //acct2取款400
		System.out.print(acct1.toString());
		System.out.print(acct2.toString());
		System.out.println(acct3.toString());
		//分别对三个账号加息
		acct1.addInterest();
		acct2.addInterest();
		acct3.addInterest();
		System.out.print(acct1.toString());
		System.out.print(acct2.toString());
		System.out.print(acct3.toString());
	}
}

AcctNumber: 60000001 Name: Alice Balance: 522.0 AcctNumber: 60000002 Name: Eric Balance: 2322.0 AcctNumber: 60000003 Name: Lia Balance: 22222.0 AcctNumber: 60000001 Name: Alice Balance: 540.27 AcctNumber: 60000002 Name: Eric Balance: 2403.27 AcctNumber: 60000003 Name: Lia Balance: 22999.77

期中测试

Test 1. 求15以内的正奇数之和

-------------------------2016-11-11更新

/*
 * 1. 求15以内的正奇数之和；即求1+3+5+7+9+11+13+15的和。
 */
public class OddNumberSum
{
	public static void main(String[] args)
	{
		int sum = 0;
		for (int i = 0; i <= 15; i++)
		{
			if (i % 2 == 1) sum += i;
		}
		System.out.println("15以内的正奇数之和为" + sum);
	}
}

15以内的正奇数之和为64

Test 2. 新版猜数字

import java.util.Scanner;
/*
 * 6. 猜数字新版。
 * 规定：生成一个100以内的整数，
 * 只给提示猜大了或猜小了，直到猜对为止；
 * 并统计次数
 */
public class GussNumberNew
{
	public static void main(String[] args)
	{
		//生成一个 1-100 的随机数
		int randomDigit = (int) (Math.random()*100 + 1);
		int gussNumber; //猜的数字
		int count = 0;  //猜的次数
		Scanner scan = new Scanner(System.in);
		//System.out.println(randomDigit);
		do
		{
			count++;
			System.out.print("请输入一个100以内的整数：");
			gussNumber = scan.nextInt();
			if (gussNumber < randomDigit)
				System.out.println("抱歉，猜小了。");
			if (gussNumber > randomDigit)
				System.out.println("抱歉，猜大了。");
		} while (gussNumber != randomDigit);
		System.out.println("您猜了" + count + "次。");
		System.out.println("恭喜您，猜对啦！");
		scan.close();
	}
}

请输入一个100以内的整数：50 抱歉，猜大了。请输入一个100以内的整数：25 抱歉，猜大了。请输入一个100以内的整数：12 抱歉，猜大了。请输入一个100以内的整数：6 抱歉，猜小了。请输入一个100以内的整数：9 抱歉，猜小了。请输入一个100以内的整数：10 抱歉，猜小了。请输入一个100以内的整数：11 您猜了7次。恭喜您，猜对啦！

Test 3 读取urls.inp文件，并以“/”为分隔符将前后的内容按行输出

www.google.com www.linux.org/info/gnu.html thelyric.com/canlender/ www.cs.vt.edu/undergraduate/about youtube.com/watch?v=EHCRimwRGLs

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
/*
 * 3. 读取urls.inp文件，并以“/”为分隔符将前后的内容按行输出。
 */
public class TextFileInputTest
{
	public static void main(String[] args)
	{
		//文件放在项目路径下（相对路径）
		String fileName = "urls.inp";
		Scanner inputStream = null;
		Scanner scan = null;
		try
		{
			inputStream = new Scanner(new File( fileName));
		} catch (FileNotFoundException e)
		{
			System.out.println("Error opening the file " + fileName);
			System.exit(0);
		}
		while (inputStream.hasNextLine())
		{
			String line = inputStream.nextLine();
			System.out.println("URL: " + line);
			scan = new Scanner(line);
			scan.useDelimiter("/");
			while (scan.hasNext())
				System.out.println("   "+scan.next());
			System.out.println();
		}
		scan.close();
		inputStream.close();
	}
}

URL: www.google.com www.google.com URL: www.linux.org/info/gnu.html www.linux.org info gnu.html URL: thelyric.com/canlender/ thelyric.com canlender URL: www.cs.vt.edu/undergraduate/about www.cs.vt.edu undergraduate about URL: youtube.com/watch?v=EHCRimwRGLs youtube.com watch?v=EHCRimwRGLs

Test 4 将用户输入的一行字符串分解到单词

import java.util.ArrayList;
import java.util.Scanner;
/*
 * 4.将用户输入的一行字符串分解到单词，加入ArrayList<String>类型
 * 的变量 inputList中，输出inputList的各元素分正序和逆序输出。
 */
public class InputStringTest
{
	public static void main(String[] args)
	{
		ArrayList<String> inputList = new ArrayList<>();
		Scanner scan = new Scanner(System.in);
		System.out.print("请输入一行单词以空格分隔：");
		String line = scan.nextLine();
		//I like you
		//字符串分割
		String arrayStr[] = line.split(" ");
		for (String string : arrayStr)
		{
			inputList.add(string);
		}
		//正序输出
		for (String word : inputList)
		{
			System.out.print(word + " ");
		}
		System.out.println();
		//逆序输出
		for (int i = inputList.size()-1; i >= 0 ; i--)
		{
			System.out.print(inputList.get(i) + " ");
		}
		scan.close();
	}
}

请输入一行单词以空格分隔：I like you I like you you like I

Test 5 生成Temperatures.java和TemperatureInfo.java两个类


import java.util.ArrayList;
/* 5.1 Temperatures类：
 * 定义ArrayList<Integer>类型的动态数组temperature,用以存储用户输入的温度数据。
 * getLowestTemp()和getHighestTemp()方法分别 返回输入的最大温度值和最小温度值；
 * toString()方法输出所有输入的温度 及  最大值、最小值。
 * 然后加入两个方法：lowerMinimun(int lowIn)和higherMaximum(int highIn)
 * 用来比较与之前输入的多个温度的最小值和最大值，从而输出两者之间的较小值和较大值。
 */
public class Temperatures
{
	ArrayList<Integer> temperature;// 存储用户输入的温度数据
	Temperatures(ArrayList<Integer> temperaturesIn)
	{
		if (temperaturesIn == null) //空对象则new
		{
			temperaturesIn = new ArrayList<Integer>();
		}
		temperature = temperaturesIn;
		//temperature.add(0); //默认添加一个元素
	}
	// 输入一个温度，返回此时的最小值
	public int lowerMinimun(int lowIn)
	{
		temperature.add(lowIn);
		return (getLowestTemp());
	}
	// 输入一个温度，返回此时的最大值
	public int higherMaximum(int highIn)
	{
		temperature.add(highIn);
		return getHighestTemp();
	}
	// 返回此最小温度值
	public int getLowestTemp()
	{
		int min = temperature.get(0);//至少有一个元素，否则报错
		for (int i = 1; i < temperature.size(); i++)
		{
			if (temperature.get(i) < min)
				min = temperature.get(i);
		}
		return min;
	}
	// 返回此最大温度值
	public int getHighestTemp()
	{
		int max = temperature.get(0);//至少有一个元素，否则报错
		for (int i = 1; i < temperature.size(); i++)
		{
			if (max < temperature.get(i))
				max = temperature.get(i);
		}
		return max;
	}
	//输出所有输入的温度 及  最大值、最小值。
	@Override
	public String toString()
	{
		String output;
		output = "\tTemperatures："
				+ temperature.toString()
				+ "\n\tLow is ：" + getLowestTemp()
				+ "\n\tHigh is：" + getHighestTemp();
		return output;
	}
	public static void main(String[] args)
	{
		ArrayList<Integer> tList = new ArrayList<Integer>();
		tList.add(3);
		tList.add(2);
		tList.add(5);
		tList.add(6);
		Temperatures temps = new Temperatures(tList);
		System.out.println(temps.toString());
		temps.lowerMinimun(1);
		temps.higherMaximum(66);
		System.out.println(temps.toString());
	}
}

	Temperatures：[3, 2, 5, 6]
	Low is ：2
	High is：6
	Temperatures：[3, 2, 5, 6, 1, 66]
	Low is ：1
	High is：66

import java.util.ArrayList;
import java.util.Scanner;
/*
 * 5.2 TemperatureInfo类：
 * 接收用户输入的多个温度值（以” ”为结束标识）。
 * 创建Temperatures 类型的temps对象引用变量，
 * 根据用户输入的字符来决定调用相应的方法。
 */
public class TemperaturesInfo
{
	public static void main(String[] args)
	{
		//Temperatures temps = new Temperatures(null);
		ArrayList<Integer> tList = new ArrayList<Integer>();
		Scanner scan = new Scanner(System.in);
		do
		{
			System.out.print("Please input the temperates：");
			String temp = scan.nextLine();
			//输入的第一个字符为空格则结束接收
			if (temp.toCharArray()[0] == ' ') break;
			tList.add( Integer.parseInt(temp) );
		} while (true);
		Temperatures temps = new Temperatures(tList);
		//[L]ow temp, [H]eigh temp, [P]rint, [E]nd: "
		String menu = "Enter choice - [L]ow temp, [H]eigh temp, [P]rint, [E]nd: ";
		while (true) 
		{
			char choice;
		    System.out.println(menu);
	        choice = scan.nextLine().charAt(0);
			if (choice != 'L' && choice != 'l' && choice != 'H' && choice != 'h' 
					&& choice != 'p' && choice != 'P' && choice != 'e' && choice != 'E' )
			{
					System.out.println
					("Your selection is incorrect, please re-enter!\n");
					continue;
			}
			switch (choice)
			{
			case 'L':
			case 'l':
				System.out.println("\tLow is ：" + temps.getLowestTemp());
				System.out.println();
				break;
			case 'H':
			case 'h':
				System.out.println("\tHigh is：" + temps.getHighestTemp());
				System.out.println();
				break;
			case 'P':
			case 'p':
				System.out.println(temps.toString());
				System.out.println();
				break;
			case 'E':
			case 'e':
				scan.close();   //关闭输入
				System.out.println("Exiting the program...");
				System.exit(0); //终止当前正在运行的 Java 虚拟机。
			}
		}
	}
}

Please input the temperates：12
Please input the temperates：-20
Please input the temperates：100
Please input the temperates：56
Please input the temperates：-35
Please input the temperates： 
Enter choice - [L]ow temp, [H]eigh temp, [P]rint, [E]nd: 
l
	Low is ：-35
Enter choice - [L]ow temp, [H]eigh temp, [P]rint, [E]nd: 
h
	High is：100
Enter choice - [L]ow temp, [H]eigh temp, [P]rint, [E]nd: 
p
	Temperatures：[12, -20, 100, 56, -35]
	Low is ：-35
	High is：100
Enter choice - [L]ow temp, [H]eigh temp, [P]rint, [E]nd: 
e
Exiting the program...

week6

6 Cylinder(一)

-------------------------2016-11-12更新

package week6;
import java.text.DecimalFormat;
/*
 * 6.1 创建 Cylinder类，以存储标签、半度；
 * 方法包括获得及设置这些成员变量，计算直径、周长面积及体积。 
 */
public class Cylinder
{
	private String lable; //存储标签
	private double radius; //圆柱半径
	private double height; //圆柱的高
	Cylinder(String lable, double radius, double height)
	{
		this.lable = lable;
		this.radius = radius;
		this.height = height;
	}
	public String getLable()
	{
		return lable;
	}
	public boolean setLable(String lable)
	{
		boolean flag = true;
		if (lable.isEmpty()) flag = false;
		else this.lable = lable.trim();
		//String.trim()截去字符串开头和末尾的空白
		return flag;
	}
	public double getRadius()
	{
		return radius;
	}
	public void setRadius(double radius)
	{
		this.radius = radius;
	}
	public double getHeight()
	{
		return height;
	}
	public void setHeight(double height)
	{
		this.height = height;
	}
	//返回圆柱底面直径
	public double diameter()
	{
		return radius * 2;
	}
	//返回圆柱底面周长
	public double circumference()
	{
		return diameter() * Math.PI;
	}
	//返回 表面积 = 圆柱底面积×2 + 底面周长×高
	public double area()
	{
		return Math.PI * radius * radius * 2
				+ circumference() * height;
	}
	//返回 圆柱底体积
	public double volumn()
	{
		return Math.PI * radius * radius * height;
	}
	@Override
	public String toString()
	{
		String output = null;
		DecimalFormat df = new DecimalFormat("#,##0.0##");
		output = lable
				+ " is a cylinder with radius = " + df.format(radius)
				+ " units and height = " + df.format(height)
				+ " units, "
				+ "\nwhich has diameter = " + df.format(diameter())
				+ " units, circumference = " + df.format(circumference())
				+ " units, "
				+ "\narea = " + df.format(area())
				+ " square units, and volume = " + df.format(volumn())
				+ " cubic units.\n";
		return output;
	}
	public static void main(String[] args)
	{
		Cylinder c1 = new Cylinder("Small Example", 4.0, 10.0);
		Cylinder c2 = new Cylinder("Medium Example", 22.1, 30.6);
		Cylinder c3 = new Cylinder("Large Example", 100.0, 200.0);
		c1.setLable("");
		System.out.println(c1);
		System.out.println(c2);
		System.out.println(c3);
	}
}

Small Example is a cylinder with radius = 4.0 units and height = 10.0 units, 
which has diameter = 8.0 units, circumference = 25.133 units, 
area = 351.858 square units, and volume = 502.655 cubic units.
Medium Example is a cylinder with radius = 22.1 units and height = 30.6 units, 
which has diameter = 44.2 units, circumference = 138.858 units, 
area = 7,317.837 square units, and volume = 46,952.189 cubic units.
Large Example is a cylinder with radius = 100.0 units and height = 200.0 units, 
which has diameter = 200.0 units, circumference = 628.319 units, 
area = 188,495.559 square units, and volume = 6,283,185.307 cubic units.

package week6;
import java.util.Scanner;
/*
 * 6.2  CylinderApp 测试类
 * 输入 标签、半径及高度，并初始化对象
 */
public class CyliderApp
{
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		String lable;
		double radius;
		double height;
		System.out.println("Enter label, radius and height for a cylinder.");
		System.out.print("\tlable: ");
		lable = scan.nextLine();
		System.out.print("\tradius: ");
		radius = Double.parseDouble(scan.nextLine());
		System.out.print("\theight: ");
		height = Double.parseDouble(scan.nextLine());
		scan.close();
		Cylinder cylinder = new Cylinder(lable, radius, height);
		System.out.println(cylinder);
	}
}

Enter label, radius and height for a cylinder. lable: Small Example radius: 4.0 height: 10.0 Small Example is a cylinder with radius = 4.0 units and height = 10.0 units, which has diameter = 8.0 units, circumference = 25.133 units, area = 351.858 square units, and volume = 502.655 cubic units.

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