一道很简单的题。toString()失误好几次

//注意：1.oString() 方法有返回值，return后为一个字符串。

//2.子类需要用到父类的toString()返回值时，直接在子类重写方法的return后加super.toString()。

/*

编写程序实现下图所示人员类的继承结构并输出相应信息。

再写一个测试类，分别输出教师和学生的行为。

*/

class Person{	
	private String name;
	private int num;
	private String sex;
	private int age;
	Person(){ }
	Person(String name,int num,String sex,int age){
		this.name = name;
		this.num = num;
		this.sex = sex;
		this.age = age;
	}
	public String toString(){
		return "姓名："+name+"  编号："+num+"  性别："+sex+"  年龄："+age;
	} 
}

class Teacher extends Person{
	private String dept;
	private String job;

	Teacher(String name,int num,String sex,int age,String job,String dept){
		super(name,num,sex,age);
		this.dept = dept;
		this.job = job;
	}

	public String toString(){
		return super.toString()+"  职务:"+job+"  部门:"+dept;

	}
	
}

class Student extends Person{
	private int stuNum;

	Student(String name,int num,String sex,int age,int sno){
		super(name,num,sex,age);
		stuNum = sno;	
	}
	public String toString(){
		return super.toString()+"  学号:"+stuNum;
	}
}

class Test{
	public static void main(String[]args){
		Teacher t = new Teacher("老张",12345,"男",34,"科长","教学科");
		System.out.println(t);
		Student s = new Student("小刘",12345,"女",19,567890);
		System.out.println(s);
	}
}