JAVA继承问题
0
2020-03-14
子类拥有父类非private的属性，方法；子类可以拥有自己的属性和方法，即子类可以对父类进行扩展；子类可以用自己的方式实现父类的方法（重定义）。
测试代码
public class A {
int i = 10;
public void add(){
System.out.println("add function in Class A is running...");
i = i + 2;
System.out.print("i = " + i);
}
public static void main(String []args) {
A a = new B();
System.out.println("before running function add: a.i = " + a.i);
a.add();
System.out.println("after running function add: a.i = " + a.i);
}
}
class B extends A{
int i = 20;
public void add(){
System.out.println("add function in Class B is running...");
i = i + 3;
System.out.print("i = "+i);
}
}
运行结果
before running function add: a.i = 10
add function in Class B is running...
i = 23after running function add: a.i = 10