c#结构函数使用了未赋值的局部变量

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ex0603
{
class Program
{
struct order
{
public string itemName;
public int unitCount;
public double unitCost;
public double Money()
{
return unitCost * unitCount;
}
}
static void Main(string[] args)
{
order myOrder;
Console.WriteLine("数量：");
myOrder.unitCount = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("单价：");
myOrder.unitCost = Convert.ToDouble(Console.ReadLine());

Console.WriteLine(myOrder.Money());

}
}
}

我编译程序时，出错说最后一行，使用了未赋值的局部变量 myOrder。不知道为什么

Answer 1

实例化：
static void Main(string[] args)
{
order myOrder=new order();
Console.WriteLine("数量：");
myOrder.unitCount = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("单价：");
myOrder.unitCost = Convert.ToDouble(Console.ReadLine());

Console.WriteLine(myOrder.Money());

}

或者可以使用静态：
namespace ex0603
{
class Program
{
public static struct Order
{
public string itemName;
public int unitCount;
public double unitCost;
public double Money()
{
return unitCost * unitCount;
}
}
static void Main(string[] args)
{
Console.WriteLine("数量：");
Order.unitCount = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("单价：");
Order.unitCost = Convert.ToDouble(Console.ReadLine());

Console.WriteLine(myOrder.Money());

}
}
}

Answer 2

static void Main(string[] args)
{
order myOrder =new order();
Console.WriteLine("数量：");
myOrder.unitCount = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("单价：");
myOrder.unitCost = Convert.ToDouble(Console.ReadLine());
Console.WriteLine(myOrder.Money());
}

把order 实例化下

Answer 3

呵呵,这个很简单的 在声明order 时候 这样写 order myOrder;=new order(); 就可以了