程序填空: public class People{ public String name; public int age; public People(){ } public People(String name,int age){ this.name=name; this.age=age; } public String Getname(){ return name+","+age; } } public class Student extends People{ public float height; public Student(){ ______; //调用父类无参构造方法 } public Student(String name,int age,float height){ _______; //调用父类的构造方法完成name和age的初始化 this.heigth=height; } public void show(){ System.out.println(_______+","+height); //调用父类的Getname方法显示三个属性的值 } public static void main(String[] args){ Student s1=new Student("",19,1.90f); System.out.println(s1.Getname()); //该行打印输出什么? s1.show(); //该行打印输出什么? } }