20200413-1

package com.test;
class Dog {
    public Dog() {
        age = 1;
        color = "Black";
        System.out.println("Default Constructor Dog");
    }
    public Dog(int ag, String clr) {
        age = ag;
        color = clr;
    }
    String breed;
    int age;
    String color;
    void barking() {}
    int hungry() { int a = 1; int b = 2; int c = a + b; return c;}
    void steeping() {}    
}
public class Test1 {
    public static void main(String[] args) {
        //Dog d = new Dog();
        Dog d2 = new Dog(2, "땡칠이");
        int s = d2.hungry();    
    }
}
/////////////////////////////////////////////////////////
package com.test;
 
public class Test2 {
 
    public static void main(String[] args) {
        String str = new String("test");
        String str1 = new String("test");
        String str2 = "test";
        String str3 = "test";
        if(str == str1) {
            System.out.println("Ok");
        }
        if(str.equals(str1)) {
            System.out.println("Ok2");
        }
        if(str2 == str3) {
            System.out.println("Ok3");
        }
 
    }
 
}
/////////////////////////////////////////////////////////
package com.test;
 
class Calculator {
    int result;
    public Calculator() {
        result = 0;
    }
    public Calculator(int r) {
        result = r;
    }
    int add(int a, int b) {
        result = a + b;
        return result;
    }
    int subtract(int a, int b) {
        result = a - b;
        return result;
    }
    // Method Overloding
    int add(int a, int b, int c) {
        result = a + b + c;
        return result;
    }
}
public class Test3 {
    public static void main(String[] args) {
        //Calculator calc = new Calculator();
        Calculator calc = new Calculator(100);
        int a = 1;
        int b = 2;
        int result = calc.add(a, b);
        System.out.println(result);        
        
    }
 
}
/////////////////////////////////////////////////////////
package com.test;
class Student {
    public void gotoSchool() {
        System.out.println("Student go to school");
    }
    public void study() {
        System.out.println("Student study");
    }
}
class MiddleStudent extends Student {
    public void study2() {
        System.out.println("MiddleStudent study");
    }
}
public class Test4 {
    public static void main(String[] args) {
        MiddleStudent stu = new MiddleStudent();
        stu.gotoSchool();
        stu.study();
        stu.study2();
    }
}
/////////////////////////////////////////////////////////
package com.test;
 
class Student2 {
    String name;
    int age;
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }
}
public class Test5 {
    public static void main(String[] args) {
        Student2 stu = new Student2();
        stu.setName("홍길동");
        stu.setAge(30);
 
    }
 
}
 
/////////////////////////////////////////////////////////
package com.test;
class A {
    int aValue;
    public A() {
        System.out.println("Default Constructor A");
        this.aValue = 10;
    }
    public A(int aValue) {
        System.out.println("Constructor A");
        this.aValue = aValue;
    }
}
 
class B extends A {
    int bValue;
    public B() {
        System.out.println("Default Constructor B");
        this.bValue = 100;
    }
    public B(int bValue) {
        super(bValue);
        this.bValue = bValue;
        System.out.println("Constructor B " + bValue + ", " + this.aValue);
    }
}
public class Test6 {
    public static void main(String[] args) {
        B b = new B(100);
    }
}
 
/////////////////////////////////////////////////////////
package com.test;
class Student4 {
    String name;
    public Student4(String name) {
        this.name = name;
    }
} 
class MiddleStudent4 extends Student4 {
    int age;
    public MiddleStudent4(String name, int age) {        
        super(name);        
        //this.name = name;
        this.age = age;
        System.out.println(name + ", " + age);
    }    
}
public class Test7 {
    public static void main(String[] args) {
        MiddleStudent4 stu = 
                new MiddleStudent4("홍길동", 20);
 
    }
 
}
 
/////////////////////////////////////////////////////////
package com.test;
class MyClass{
    //int count;
    static int count;
    public MyClass() {
        count++;
        System.out.println(count);
    }
}
public class Test8 {
    public static void main(String[] args) {
        MyClass myClass = new MyClass();
        MyClass myClass2 = new MyClass();
        MyClass myClass3 = new MyClass();
        MyClass.count = 100;
        myClass.count = 200;
    }
 
}
/////////////////////////////////////////////////////////
package com.test;
class MyClass3 {
    int a;
    static int b;
    public static void setAValue(int x) {
        b = x;
    }
    public void setBValue(int y) {
        a = y;        
        setAValue(10);
    }    
}
public class Test9 {
    public static void main(String[] args) {
        MyClass3.b = 20;
        MyClass3 m = new MyClass3();
        m.a = 10;
        m.b = 20;
                
 
    }
}
/////////////////////////////////////////////////////////
package com.test;
class MyClass4 {
    static int a;
    static int b;
    static {
        a = 1;
        b = 2;        
        System.out.println("Static Initialize");
    }    
}
public class Test10 {
    public static void main(String[] args) {
        MyClass4 m = new MyClass4();
 
    }
}
/////////////////////////////////////////////////////////
package com.test;
class Student5 {
    String name;
    int age;
    public Student5(String name, int age) {
        this.name = name;
        this.age = age;
    }
}
class HighStudent5 extends Student5 {
    int grade;
    public HighStudent5(String name, int age, int grade) {
        super(name, age);
        this.grade = grade;
    }
    void setNameAge(String name, int age) {
        this.name = name;
        this.age = age;
    }
    void study() {
        System.out.println(name + ", " + age + ", " + grade);
    }    
}
public class Test11 {
    public static void main(String[] args) {
        HighStudent5 stu = new HighStudent5("홍길동", 20, 1);
        stu.study();
        
 
    }
}
 
/////////////////////////////////////////////////////////
package com.test;
class A2 {
    void aMethod() {System.out.println("aMethod");}
}
class B2 extends A2 {
    void bMethod() {System.out.println("bMethod");}
    void aMethod() {System.out.println("aMethod on B2 Class");}
}
class C2 extends A2 {
    void cMethod() {System.out.println("cMethod");}
    void aMethod() {System.out.println("aMethod on C2 Class");}
}
public class Test12 {
    static void callMethod(B2 b) {
        b.aMethod();
    }
    static void callMethod(C2 c) {
        c.aMethod();
    }
    static void callMethod2(A2 a) {
        a.aMethod();
    }
    public static void main(String[] args) {
        callMethod(new B2());
        callMethod(new C2());
        callMethod2(new B2());
        callMethod2(new C2());
//        B2 b = new B2();
//        b.aMethod();
//        b.bMethod();
//        A2 a = b;
//        a.aMethod();
//        B2 b1 = (B2)a;
//        b1.aMethod();
//        b1.bMethod();
//        
//        C2 c = new C2();
//        c.aMethod();
//        c.cMethod();
//        A2 a2 = c;
//        a2.aMethod();
//        C2 c2 = (C2)a2;
//        c2.aMethod();
//        c2.cMethod();
        
        B2 b2 = new B2();
        A2 a2 = b2;
        a2.aMethod();
 
 
    }
}
/////////////////////////////////////////////////////////
package com.test;
class Animal2 {
    void move() { System.out.println("Animal move");}
}
class Dog2 extends Animal2 {
    void move() { System.out.println("Dog move");}
}
class Cat2 extends Animal2 {
    void move() { System.out.println("Cat move");}
}
public class Test13 {
    static void goMove(Animal2 a) {
        a.move();
    }
    public static void main(String[] args) {
        Animal2 a = new Animal2();
        a.move();
        Dog2 d = new Dog2();
        d.move();
        Animal2 a2 = new Dog2();
        a2.move();
 
    }
 
}