Question

C#怎样为一个交错数组赋值？注意：不是初始化，是通过Console.Read等形式赋值！

附代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
class Student
{
public int num;
public string name;
public int age;
public double score;

}
static void Main(string[] args)
{
Console.WriteLine("请输入班级的数目：");
int c;
c = Convert.ToInt32(Console.ReadLine());
Student[][] stu = new Student[c][];

for (int i = 0; i < c; i++)
{

Console.Write("请输入班级序号：");
int e = Convert.ToInt32(Console.ReadLine());
Console.Write("请输入该班的人数：");
int d = Convert.ToInt32(Console.ReadLine());
stu[i] = new Student[d];
Console.WriteLine("请输入每个班的每个学生的信息:");
for (int f = 0; f < d; f++)
{
Console.Write("学号：");
stu[i][f].num = Convert.ToInt32(Console.ReadLine());
Console.Write("姓名：");
stu[i][f].name = Console.ReadLine();
Console.Write("年龄：");
stu[i][f].age = Convert.ToInt32(Console.ReadLine());
Console.Write("成绩：");
stu[i][f].score = Convert.ToDouble(Console.ReadLine());
}
}
Console.WriteLine("信息录入完毕");
}
}
}
编译能通过，但运行时总提示："未将对象引用设置到对象的实例。"我实在搞不懂了！已经被搞得焦头烂额了！这个地方老是过不去！问题补充：

每当运行到：stu[i][f].num = Convert.ToInt32(Console.ReadLine());
或是stu[i][f].name = Console.ReadLine();这些地方时就出错！
谁能帮帮我呀？我快郁闷死了！

Answer 1

for (int f = 0; f < d; f++)
{
stu[i][f] = new Student();
Console.Write("学号：");
stu[i][f].num = Convert.ToInt32(Console.ReadLine());
Console.Write("者肢姓名败旦：");
stu[i][f].name = Console.ReadLine();
Console.Write("年龄：");
stu[i][f].age = Convert.ToInt32(Console.ReadLine());
Console.Write("成绩：察嫌扰");
stu[i][f].score = Convert.ToDouble(Console.ReadLine());
}

注意：在输入学号前写上
stu[i][f] = new Student();