java面向对象入门级(4)

public B() {

super(2); //如果将本语句注释掉 则会出错，因为 “派生类构造函数中

如果不写super(...); 则默认的会添加super();” }

class TestSuper_2 { } class A { } class M {

public int i = 10; public int j = 20;

public void show() { }

System.out.printf(\

}

System.out.println(\

public static void main(String[] args) {

A aa = new A(5); B bb = new B();

}

}

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

A aa1 = new A(); A aa2 = new A(); aa1.show(); aa2.show();

class A { } class M { // // //

public static void main(String[] args) {

A aa1 = new A(); A aa2 = new A(); aa1.j = 40;

System.out.printf(\//System.out.printf(\System.out.printf(\

public int i = 10; static int j = 20;

public void f() { }

i = 88;

} /* */

}

2009年5月31日14:05:02

本程序证明了: 一个类的属性可以是个类对象

class A { } class C { } class M { } /* */

2009年5月31日14:05:02

本程序证明了: 一个类的属性可以是个类对象 public static void main(String[] args) { }

public int i = 10;

public A aa = new A(); //aa一定是个对象, aa是否也是C的属性？ 是

class A { } class C { } class M { }

class Human {

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

C cc = new C(); cc.g();

public void g() { }

aa.f();

public int i = 10;

public A aa = new A(); //aa一定是个对象, aa是否也是C的属性？ 是 public void f() { }

System.out.printf(\哈哈\\n\

}

public String name; public int age;

class Student { }

class Graduate { }

class Human { }

class Student extends Human {

public double score = 66.6; public String name = \张三\public int age = 22; public String name; public int age;

public double score;

public String daoshi; public String name; public int age;

public double score;