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  • 归档七

    课后作业1

    运行 TestInherits.java ,观察输出,总结父类与子类之间构造方法的调用关系修改Parent构造方法的代码,调用GrandParent的另一个构造函数

    class Grandparent {

        public Grandparent() {

            System.out.println("GrandParent Created.");

        }

        public Grandparent(String string) {

            System.out.println("GrandParent Created.String:" + string);

        }

    }

    class Parent extends Grandparent {

        public Parent() {

            //super("Hello.Grandparent.");

            System.out.println("Parent Created");

           // super("Hello.Grandparent.");

        }

    }

    class Child extends Parent {

        public Child() {

            System.out.println("Child Created");

        }

    }

    public class TestInherits {

        public statclass Grandparent {

        public Grandparent() {

            System.out.println("GrandParent Created.");

        }

        public Grandparent(String string) {

            System.out.println("GrandParent Created.String:" + string);

        }

    }

    class Parent extends Grandparent {

        public Parent() {

            //super("Hello.Grandparent.");

            System.out.println("Parent Created");

           // super("Hello.Grandparent.");

        }

    }

    class Child extends Parent {

        public Child() {

            System.out.println("Child Created");

        }

    }

    public class TestInherits {

        public static void main(String args[]) {

            Child c = new Child();

        }

    }

    ic void main(String args[]) {

            Child c = new Child();

        }

    }

    结论:

        通过 super 调用基类构造方法,必须是子类构造方法中的第一个语句。子类中,调用父类中被覆盖的方法,可以使用super语句

    课后作业2

    代码:

            class Parent{

        public Parent() {

           

            System.out.println("Parent Created");

        }

        public void show(){

          System.out.println("hello java !");

        }

    }

    class Child extends Parent {

        public Child(){

            System.out.println("Child Created");

    }

        public void show(){

            super.show();

         System.out.println("say hello! child!!!");

         

       }

    }

    public class Test6 {

        public static void main(String args[]) {

            Child c = new Child();

            c.show();

        }

    }

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  • 原文地址:https://www.cnblogs.com/CkmIT/p/6055621.html
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