2020.10.5 今天学了重写 super 以及继承中的构造方法，为验证学习成果来做一道练习题
class A{ protected void print(String s) { System.out.println(s); } A(){ print("A()"); } public void f() { print("A:f()"); } } class Test1 extends A { Test1(){ print("Test1()"); } public void f() { print("Test1:f()"); } public static void main(String[] args) { Test1 b = new Test1(); b.f(); } }读以上程序，判定输出结果 简单分析一下两个类，首先是父类A，它有两个方法和一个构造方法，其中A方法无参数，f方法则调用print方法来输出字符串 之后是子类Test1，它在继承了父类的方法之后还有两个方法，其中Test1调用父类的print方法，f()方法重写了父类的f()，并且还会自动调用父类中没有参数的方法 在一顿分析之后我们可以猜到最后的结果就是： A() //自动调用父类无参数 Test1() //调用父类中print方法 Test1:f() //重写了f()方法 下面进行程序的运行： 结果正确！
再来一道练习题
package haro; class YesPerson{ private String name; private String location; YesPerson(String name){ this.name = name; location = "beijing"; } YesPerson(String name,String location){ this.name = name; this.location = location; } public String info() { return("name: " + name + " location: " + location); } } class YesStudent extends YesPerson{ private String school; YesStudent(String name,String school){ this(name,"beijing",school); } YesStudent(String n , String l ,String school){ super(n,l); this.school = school; } public String info() { return(super.info() + " school: " + school); } } class YesTeacher extends YesPerson{ private String capital; YesTeacher(String name,String capital){ this(name,"beijing",capital); } YesTeacher(String n , String l ,String capital){ super(n,l); this.capital = capital; } public String info() { return(super.info() + " capital: " + capital); } } public class TestTeacher { public static void main(String[] args) { YesPerson p1 = new YesPerson("A"); YesPerson p2 = new YesPerson("B" , "shanghai"); YesStudent s1 = new YesStudent("C" , "S1"); YesStudent s2 = new YesStudent("C" , "shanghai" , "S2"); YesTeacher t1 = new YesTeacher("D" , "professor"); YesTeacher t2 = new YesTeacher("D" , "shanghai" , "principal"); System.out.println(p1.info()); System.out.println(p2.info()); System.out.println(s1.info()); System.out.println(s2.info()); System.out.println(t1.info()); System.out.println(t2.info()); } }这是一个我认为对于重载，重写，super，继承中构造方法很全面的程序 非常容易入手建议平时多看看
