在某个Visual Studio .Net的教材上看到了这样的Hello World的Code,但是在VC6里死活也不能compile.请问是为什么？难道只有VS.Net才可以？谢了

using System;

class Welcome
{
static void Main()
{
Console.WriteLine("Please Enter Your Name:");
string name = Console.ReadLine();
Console.WriteLine("Welcome to you, {0}!", name);
}
}


DEBUG:
error C2873: 'System' : symbol cannot be used in a using-declaration
fatal error C1004: unexpected end of file found