{
public string name;
public int age;
public float weight;
public Student(string a, int b, float c)
{
name = a;
age = b;
weight = c;
}
}

class Test
{
static void Main(string[] args)
{
ArrayList stuarray = new ArrayList();
string tag;
do
{
Console.Write("Enter the name:");
string tmp_name = Console.ReadLine();
Console.Write("Enter the age:");
int tmp_age = int.Parse(Console.ReadLine());
Console.Write("Enter the weight:");
float tmp_weight = float.Parse(Console.ReadLine());
stuarray.Add(new Student(tmp_name, tmp_age, tmp_weight));
Console.WriteLine("Contuine? (y/n)");
tag =Console.WriteLine();

} while (tag == 'y');

int MaxIndex = 0, Maxage = 0；
int i = 0;

for (i = 0; i < stuarray.Count;i++)
{
if ((Student)stuarray[i].age > Maxage)
{
Maxage = (Student)stuarray[i].age;
MaxIndex = i;
}
}
Console.WriteLine("The Name with Maxage is {0}", (Student)stuarray[MaxIndex].name);

}

}


请问一下后面几句有什么错，调试时老出错！说不包括age ,name 的定义！非常感谢！

请问，我这里调式还有N个错误，难道楼主只有那个错误吗？

using System;
using System.Collections;

class Student
{
public string name;
public int age;
public float weight;
public Student(string a, int b, float c)
{
name = a;
age = b;
weight = c;
}
}

class Test
{
static void Main(string[] args)
{
ArrayList stuarray = new ArrayList();
string tag;
do
{
Console.Write("Enter the name:");
string tmp_name = Console.ReadLine();

Console.Write("Enter the age:");
int tmp_age = int.Parse(Console.ReadLine());

Console.Write("Enter the weight:");
float tmp_weight = float.Parse(Console.ReadLine());

stuarray.Add(new Student(tmp_name, tmp_age, tmp_weight));

Console.WriteLine("Contuine? (y/n)");
tag = Console.ReadLine();

} while (tag == "y");

int MaxIndex = 0, Maxage = 0;
int i = 0;

Student stu = null;
for (i = 0; i < stuarray.Count;i++)
{
stu = (Student)stuarray[i];
if (stu.age > Maxage)
{
Maxage = stu.age;
MaxIndex = i;
}
}

Console.WriteLine("The Name with Maxage is {0}", stu.name);

}
}

把class Test以上的代码定义为一个方法，然后放到class Test这个类里面试试,不过要注意一下静态的问题

或者这样

for (i = 0; i < stuarray.Count;i++)
{
if (((Student)stuarray[i]).age > Maxage)
{
Maxage = ((Student)stuarray[i]).age;
MaxIndex = i;
}
}
Console.WriteLine("The Name with Maxage is {0}", ((Student)stuarray[MaxIndex]).name);

非常感谢楼上的朋友！