使用未分配的局部变量（即使已声明）

Question

我正在尝试制作一个简单的计算器，但出现此错误“使用未分配的变量'运算'

它仅在语句开头的一行中给出错误

此处：if（ operation ==“ x”）

整件事：

 static void Main()
    {
        int firstNumber;
        int secondNumber;
        string operation;
        int answer;

        Console.WriteLine("Hello welcome to Eral's Calculator");
        Console.ReadLine();

        Console.Write("Enter the first number for the equation");
        firstNumber = Convert.ToInt32(Console.ReadLine()); 

        Console.WriteLine("Enter the second number for the equation");
        secondNumber = Convert.ToInt32(Console.ReadLine());


        if (operation == "x")
        {

            answer = firstNumber * secondNumber;
            Console.WriteLine(firstNumber + "x" + secondNumber + " = " + answer);
            Console.ReadLine();
        }
        else if (operation == "+")
        {
            answer = firstNumber + secondNumber;
            Console.WriteLine(firstNumber + "+" + secondNumber + " = " + answer);
            Console.ReadLine();

        }
        else if (operation == "-")
        {
            answer = firstNumber - secondNumber;
            Console.WriteLine(firstNumber + "-" + secondNumber + " = " + answer);
            Console.ReadLine();
        }
        else if (operation == "/")
        {
            answer = firstNumber / secondNumber;
            Console.WriteLine(firstNumber + "/" + secondNumber + "=" + answer);
            Console.ReadLine();

        }
        else
        {
            Console.WriteLine("That is not how you calculate, Try Again?");  
            Console.ReadLine();
        }
    }

Answer 1

您需要捕获operation的值。

例如：

    Console.WriteLine("Enter the operation type");
    operation = Console.ReadLine();

Answer 2

在我看来，操作从未设置为任何东西？