请问一下错误在那里？？？顺便问一下，构造函数语法怎么一回事？

class Human
{char name[20];int age;
 public:
        Human(char *n,int a)
        {strcpy(name,n); age=a;}
};
class Student:public Human
{int id,grade;
 public:
         Student(char *n,int a,int i,int g):Human(*n,a)
         {  id=i;               grade=g;              }
};

Student xs(name,age,id,grade);

请问一下错误在那里？？？
顺便问一下，构造函数语法怎么一回事？