simpleinheritance.java

Java 程序设计源码 只提供了部分

class A {
	int i,j;

	void showij() {
		System.out.println("i and j:" + i + " " + j);
	}
} 

class B extends A {
	int k;
	
	void showk() {
		System.out.println("k:"  + k);
	}

	void sum() {
		System.out.println("i + j + k: " + (i + j + k));
	}
}

class SimpleInheritance {
	public static void main(String[] args) {
		A superOb = new A();
		B subOb = new B();

		System.out.println("Contents of superOb:");

		superOb.i = 10;
		superOb.j = 20;
	
		superOb.showij();

		System.out.println();

		System.out.println("Contents of wuperOb");

		subOb.i = 7;
		subOb.j = 8;
		subOb.k = 9;

		subOb.showij();
		subOb.showk();	

		System.out.println();

		subOb.sum();
	}
}