JavaEssential Practices

JavaEssential_.idea_checkstyle-idea.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="CheckStyle-IDEA">
    <option name="configuration">
      <map>
        <entry key="checkstyle-version" value="8.8" />
        <entry key="copy-libs" value="false" />
        <entry key="location-0" value="BUNDLED:(bundled):Sun Checks" />
        <entry key="location-1" value="BUNDLED:(bundled):Google Checks" />
        <entry key="scan-before-checkin" value="false" />
        <entry key="scanscope" value="JavaOnly" />
        <entry key="suppress-errors" value="false" />
      </map>
    </option>
  </component>
</project>

JavaEssential_.idea_JavaEssential.iml

<?xml version="1.0" encoding="UTF-8"?>
<module type="JAVA_MODULE" version="4">
  <component name="NewModuleRootManager" inherit-compiler-output="true">
    <exclude-output />
    <content url="file://$MODULE_DIR$" />
    <orderEntry type="inheritedJdk" />
    <orderEntry type="sourceFolder" forTests="false" />
  </component>
</module>

JavaEssential_.idea_misc.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ProjectRootManager" version="2" project-jdk-name="1.8" project-jdk-type="JavaSDK" />
</project>

JavaEssential_.idea_modules.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ProjectModuleManager">
    <modules>
      <module fileurl="file://$PROJECT_DIR$/.idea/JavaEssential.iml" filepath="$PROJECT_DIR$/.idea/JavaEssential.iml" />
    </modules>
  </component>
</project>

JavaEssential_Cat.java

package com.Ethan.JavaTest;

public class Cat {

	private static int cid = 0;
	private String name;
	private int id;

	Cat(String name) {
		this.name = name;
		this.id = cid++;
	}

	public void info() {
		System.out.println("Cat name: " + name + " | No." + id);
	}


	public static void main(String[] args) {
		Cat.cid = 1000;

		Cat c1 = new Cat("Dudu");
		Cat c2 = new Cat("Mimi");
		Cat.cid = 2000;
		Cat c3 = new Cat("Titi");

		c1.info();
		c2.info();
		c3.info();

	}

}

JavaEssential_Dog.java

public class Dog {
	static int furColor;
	float weight;
	float height;

	static class Mouse {
		//
	}

	void catchMouse(Mouse m) {
		//m.scream();
		System.out.println("Catching mouse.");
	}


	public static void main(String[] args) {
		int i=9;
		System.out.println(i);

		Dog d = new Dog();
		Mouse m = new Mouse();
		d.catchMouse(m);

	}
}

JavaEssential_FibonacciSequence.java

class Fibonacci {
	public long f(int n) {
		if(n==1||n==2) return 1;
		else 
			return f(n-1) + f(n-2);
	}
}


public class FibonacciSequence {	
	public static void main(String[] args) {
		int target = 47;
		Fibonacci fs = new Fibonacci();
		System.out.println( "Fibonacci target:" + fs.f(target) + "\n" );

		for( int i = 1; i <= target; i++) {
			System.out.println("F("+i+"):" + fs.f(i));
		}
	}
}

JavaEssential_HelloWorld.java

public class HelloWorld {

	public static void main(String[] args) {
		print();		
	}

	private static void print() {
		System.out.println("HelloEthan!");
	}
	
	
	public String getName() {
		return hiEthan();
	}

	private String hiEthan() {
		return "Hello Ethan";
	}

}

JavaEssential_Leaf.java

public class Leaf {

	int i = 0;

	Leaf(int i) {
		this.i = i;
	}

	Leaf increament() {
		i++;
		return this;
	}

	void print() {
		System.out.println("i = " + i);
	}

	public static void main(String[] args) {
		Leaf leaf = new Leaf(100);
		leaf.increament().increament().print();
	}
}

JavaEssential_OddSum.java

public class OddSum {
	public static void main(String[] args) {
		long result = 0;
		for(int i=1; i<=99; i+=2) {
			result += i;
		}
		System.out.println("Result = " + result);
	}
}

JavaEssential_PrimeNumber.java

public class PrimeNumber {
	public static void main(String[] args) {
		//101~200 Prime Number
		int totalNum = 0;
		for(int i = 101; i < 200; i+=2) {
			boolean flag = false;
			for(int j = 2; j < i; j++) {
				if(i%j == 0) {
					flag = true;
					break;
				}
			}
			if(!flag) {
				totalNum++;
				System.out.print(i+" ");
			}
		}
		System.out.println();
		System.out.println("Total number is " + totalNum);
	}
}

JavaEssential_StringCount.java

public class StringCount {

  public int countNum(String str)  {
    int num = 0;
    for(int i=0;i<str.length();i++) {
      str.charAt(i);
      return num;
    }
  }

  public static void main(String[] args) {

    String s = "AaaaaaBBCNMCMHJ827349829%^&*hahkcjkKCJKH";
    Stri
  }
}

JavaEssential_Test.java

public class Test {
	public static void main(String[] args) {
		System.out.println("Hello World!!!");
	}
}

JavaEssential_TestBreak.java

public class TestBreak {
	public static void main(String[] args) {
		int stopSign = 4;
		for(int i = 1; i < 10; i++) {
			if(i == stopSign) break;
			System.out.print(i + " ");
		}
	}
}

JavaEssential_TestCircle.java

class Point {
	private double x;
	private double y;

	Point() {
		x = 0.0;
		y = 0.0;
	}

	Point(double _x, double _y) {
		x = _x;
		y = _y;
	}

	public double getPointX() {
		return x;
	}

	public double getPointY() {
		return y;
	}

	public void setPointX(double _x1) {
		x = _x1;
	}

	public void setPointY(double _y1) {
		y = _y1;
	}
}

class Circle {
	private Point o;
	private double radius;

	Circle(Point p, double r) {
		o = p;
		radius = r;
	}

	Circle(double r) {
		o = new Point();
		radius = r;
	}

	boolean containPoint(Point tp) {
		double x = tp.getPointX() - o.getPointX();
		double y = tp.getPointY() - o.getPointY();
		return ( radius*radius > x*x + y*y) ? true : false;
	}

	public void setO(double x, double y) {
		o.setPointX(x);
		o.setPointY(y);
	}

	public Point getO() {
		return o;
	}

	public double getRadius() { return radius; }

	public void setRadius(double r) { radius = r; }

	public double getArea() {
		return 3.14 * radius * radius;
	}

}

public class TestCircle {
	public static void main(String[] args) {
		
		Circle c1 = new Circle(new Point(1.0, 2.0), 2.0);
		Circle c2 = new Circle(5.0);

		c1.getO().setPointX(4.0);
		c1.setRadius(3.0);

		System.out.println("c1:(" + c1.getO().getPointX() + "," + c1.getO().getPointY() + ") " + c1.getRadius() + " " + c1.getArea());
		System.out.println("c2:(" + c2.getO().getPointX() + "," + c2.getO().getPointY() + ") " + c2.getRadius() + " " + c2.getArea());


		Point checkPoint1 = new Point(6.0, 3.0);
		System.out.println("Circle c1 contain the check Point(6,3)? : " + c1.containPoint(checkPoint1) );
		System.out.println("Circle c2 contain the check Point(6,3)? : " + c2.containPoint(checkPoint1) );


		Point checkPoint2 = new Point(3.0, 3.0);
		System.out.println("Circle c1 contain the check Point(3,3)? : " + c1.containPoint(checkPoint2) );
		System.out.println("Circle c2 contain the check Point(3,3)? : " + c2.containPoint(checkPoint2) );

	}
}

JavaEssential_TestContinue.java

public class TestContinue {
	public static void main(String[] args) {
		int continueSign = 4;
		for(int i = 1; i < 10; i++) {
			if(i == continueSign) continue;
			System.out.print(i + " ");
		}
	}
}

JavaEssential_TestDividedBy3.java

public class TestDividedBy3 {
	public static void main(String[] args) {
		int num = 0;
		for(int i=1; i<100; i++) {
			if(i%3 == 0) {
				num ++;
				System.out.print(i + " ");
				if(num == 12) break;
			}
		}
	}
}

JavaEssential_TestFor.java

public class TestFor {
	public static void main(String[] args) {
		long result = 0;
		long f = 1;
		for (int i = 1; i <= 10; i++) {
			f = f * i;
			result += f;
		}
		System.out.println("result=" + result);
	}
}

JavaEssential_TestInherit.java

class FatherClass {
	public int value;
	public void f() {
		value = 100;
		System.out.println("FatherClass.value=" + value);
	}
}

class ChildClass extends FatherClass {
	public int value;
	public void f() {
		super.f();
		value = 200;
		System.out.println("ChildClass.value=" + value);
		System.out.println(value);
		System.out.println(super.value);
	}
}

public class TestInherit {
	public static void main(String[] args) {
		// FatherClass fc = new FatherClass();
		// fc.f();
		ChildClass cc = new ChildClass();
		cc.f();
	}
}

JavaEssential_TestOverload.java

class Person {
	protected int id;
	protected int age;
	
	Person() {
		id = 100;
		age = 1;
	}

	Person(int _id) {
		id = _id;
	}

	Person(int _id, int _age) {
		id = _id;
		age = _age;
	}

	

	void info() {
		System.out.println("Empty Method Called.");
	}

	void info(String t) {
		System.out.println(t + " 2nd Method Called.");
	}
}





public class TestOverload {

	public static void main(String[] args) {
		Person p = new Person();
		Person pID = new Person(101);
		Person pBoth = new Person(99, 33);

		//p.info();
		//p.info("EthanZ");

		System.out.println(p.id + " " + p.age);
		System.out.println(pID.id + " " + pID.age);
		System.out.println(pBoth.id + " " + pBoth.age);

	}
}

JavaEssential_TestOverWrite.java

class Person {
	private String name;
	private int age;

	public void setName(String name) {
		this.name = name;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public int getAge() {
		return age;
	}

	public String getInfo() {
		return "Name: " + name + "\n" +"Age: " + age;
	}

}

class Student extends Person {
	private String school;

	public void setSchool(String school) {
		this.school = school;
	}

	public String getSchool() {
		return school;
	}

	public String getInfo() {
		return "Name: " + getName() + "\n" +"Age: " + getAge() + "\n" +"School: " + getSchool();
	}

}

public class TestOverWrite {
	public static void main(String[] args) {
		Person ps = new Person();
		Student sd = new Student();

		ps.setName("none");
		ps.setAge(1000);

		sd.setName("Kira");
		sd.setAge(19);
		sd.setSchool("Tokyo Univercity");

		System.out.println(ps.getInfo());
		System.out.println(sd.getInfo());

	}
}

JavaEssential_TestPackage_Cat.java

package com.Ethan.JavaTest;

public class Cat {


}

JavaEssential_TestPackage_Dog.java

import com.Ethan.JavaTest.Cat;

public class Dog {

	public static void main(String[] args) {
		Cat c = new Cat();
	}
}

JavaEssential_TestPerson.java

class Person {
	private String name;
	private int age;

	public void setName(String name) {
		this.name = name;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public int getAge() {
		return age;
	}

}

class Student extends Person {
	private String school;

	public void setSchool(String school) {
		this.school = school;
	}

	public String getSchool() {
		return school;
	}

}

public class TestPerson {
	public static void main(String[] args) {
		Student sd = new Student();
		sd.setName("Kira");
		sd.setAge(19);
		sd.setSchool("Tokyo Univercity");

		System.out.println(sd.getName());
		System.out.println(sd.getAge());
		System.out.println(sd.getSchool());

	}
}

JavaEssential_TestPoint.java

class Point {
	double x, y, z;

	Point(double _x, double _y, double _z) {
		x = _x;
		y = _y;
		z = _z;
	}

	void setX(double _x){
		x = _x;
	}

	double getDistance(Point p) {
		return (x - p.x)*(x - p.x) + (y - p.y)*(y - p.y) + (z - p.z)*(z - p.z);
	}


}


public class TestPoint {

	public static void main(String[] args) {
		Point p1 = new Point(3.0, 4.0, 5.0);
		Point p2 = new Point(0.0, 0.0, 0.0);

		System.out.println("Done");

		p1.setX(2.0);
		
		System.out.println(p1.getDistance(p2));
		System.out.println(p1.getDistance(new Point(1.0, 1.0, 1.0)));
	}

}

JavaEssential_TestSuperFunction.java

class A {
	protected void print(String s) {
		System.out.println(s);
	}

	A() { print ("A()");}
	public void f() { print ("A:f()");}
}

class B extends A {
	B() { print("B()"); }
	public void f() { print ("B:f()");}
}

public class TestSuperFunction {
	public static void main(String[] args) {
		B b = new B();
		b.f();
	}
}

JavaEssential_TestSuperSub.java

class SuperClass {
	private int n;

	SuperClass() {
		System.out.println("SuperClass()");
	}

	SuperClass(int n) {
		System.out.println("SuperClass(" + n +")");
		this.n = n;
	}
}

class SubClass extends SuperClass {
	private int m;

	SubClass() {
		super(300);
		System.out.println("SubClass()");
		// super(); 父类构造函数必须写在第一句
	}

	SubClass(int m) {
		System.out.println("SubClass(" + m + ")");
		this.m = m;
	}
}

public class TestSuperSub {
	public static void main(String[] args) {
		// SubClass sub1 = new SubClass();
		SubClass sub2 = new SubClass(500);
	}
}

JavaEssential_TestSwitch.java

public class TestSwitch {
	public static void main(String[] args) {
		int i = 7;
		switch(i) {
			case 1:
				System.out.println(i+" exit.");
				break;
			case 3:
				System.out.println(i+" exit.");
				break;
			case 5:
				System.out.println(i+" exit.");
				break;
			case 7:
				System.out.println(i+" exit.");
				//break;
			case 9:
				System.out.println(i+" exit.");
				break;
			default:
				System.out.println("To the end. Default exit.");
		}
	}
}

JavaEssential_TestTeacher_TestTeacher.java

class Person {
	private String name;
	private String location;

	Person(String name) {
		this.name = name;
		location = "Beijing-P";
	}
	Person(String name, String location) {
		this.name = name;
		this.location = location;
	}

	public String Info() {
		return "Name:" + name + " Location:" + location;
	}

	public void print(String s) {
		System.out.println(s);
	}
}

class Student extends Person {
	private String school;

	Student(String name, String school) {
		this(name, "Beijing-S", school);
	}

	Student(String name, String location, String school) {
		super(name, location);
		this.school = school;
	}

	public String Info() {
		return super.Info() + " School:" + school;
	}
}

class Teacher extends Student {
	private String title;

	Teacher(String name, String school, String title) {
		super(name, school);
		this.title = title;
	}

	Teacher(String name, String location, String school, String title) {
		super(name, location, school);
		this.title = title;
	}

	public String Info() {
		return super.Info() + " Title:" + title;
	}

}

public class TestTeacher {
	public static void main(String[] args) {
		Person p1 = new Person("Person-1");
		Person p2 = new Person("Person-2","Shanghai");
		p1.print(p1.Info());
		p2.print(p2.Info());

		Student s1 = new Student("Student-1","PKU");
		Student s2 = new Student("Student-2","Xiamen","XMU");
		s1.print(s1.Info());
		s2.print(s2.Info());

		Teacher t1 = new Teacher("Teacher-1","XMU","Professon Level 1");
		Teacher t2 = new Teacher("Teacher-2","Xiamen","XMU","Professon Level 2");
		t1.print(t1.Info());
		t2.print(t2.Info());

	}
}

JavaEssential_TestWhile.java

public class TestWhile {
	public static void main(String[] args) {

		int i = 0;

		while (i < 10) {
			System.out.println(i);
			i++;
		}

		System.out.println("");

		i = 9;

		do {
			System.out.println(i);
			i--;
		} while( i >= 0);

	}
}