使用未分配的局部变量？

Question

Visual Studio中口口声声说Use of unassigned variable的iVal和iNumber.谁能告诉我哪里出错了？

这是一个代码,要求用户继续输入整数并将其添加到用户想要停止.然后在控制台上显示整数之和.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace AddFive
{
    class Program
    {
        static void Main(string[] args)
        {
           int iNumber;
           int iVal;
           int iTotal = 0;

            while (iVal > 0)
            {
                Console.WriteLine("Enter number " + iNumber);
                iVal = Convert.ToInt32(Console.ReadLine());
                iTotal = iTotal + iVal;
            }

            if (iNumber <= 0)
            {
                Console.WriteLine("Total = " + iTotal);
                iVal = Convert.ToInt32(Console.ReadLine());
                iTotal = iTotal + iVal;
            }

            Console.WriteLine("Total = " + iTotal);
            Console.WriteLine();
            Console.WriteLine("Press any key to close");
            Console.ReadKey();
        }
    }
}

Answer 1

为这些变量分配值.在使用它们之前,需要为局部变量赋值

    int iNumber = 0;
    int iVal = 0;

当你写的时候while (iVal > 0),iVal没有设置值

您只能使用instance/class变量来逃避它,因为它们被初始化为默认值

public class Program
{
    int i; //this was not implicitly initialized to zero (0)

    public Program()
    {
        int j; //need to initialize this before use

        Console.Write(j);  //this throws "Use of unassigned variable" error
        Console.Write(i);  //this prints 0, the default value
    }
}

Answer 2

Visual Studio是正确的,您正在尝试引用未初始化的变量.

试试这个:

 int iNumber = 0;
 int iVal = 0;

这样,您正在将变量初始化为初始值0.原始问题出现在这些行上:

while (iVal > 0) 和 if (iNumber <= 0)

在为变量赋值之前,您尝试访问变量.