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 show(){ return name+","+age; } } public class Student extends People{ public float height; public Student(String name,int age,float height){ super.name=name; super.age=age; this.heigth=height; } ______String _____{ //重写show方法 return name+","+age+","+______; //返回三个属性值连接的字符串 } public static void main(String[] args){ People p1=new People("张三",20); Student s1=new Student("五",19,1.90f); System.out.println(p1.show()); //该行打印输出什么? System.out.println(s1.show()); //该行打印输出什么? } }