c# - 变量不会响应输入而更改其值

Question

我实际上对编程很陌生，也许我只是累了，但我找不到这里的问题。 result 似乎没有改变它的值。如您所见，第一个输入是 product，第二个是 city，最后是我们想要的那个产品的 amount。该程序必须打印最终价格(result)。

static void Main(string[] args)
{
    string product = Console.ReadLine().ToLower();
    string city = Console.ReadLine().ToLower();
    double amount = double.Parse(Console.ReadLine());
    double result;
    if (city == "Sofia")
    {
        if (product == "coffee")
        {
            result = amount * 0.50;
            Console.WriteLine(result);

        }
        else if (product == "water")
        {
            result = amount * 0.80;
            Console.WriteLine(result);

        }
        else if (product == "beer")
        {
            result = amount * 1.20;
            Console.WriteLine(result);

        }
        else if (product == "sweets")
        {
            result = amount * 1.45;
            Console.WriteLine(result);

        }
        else if (product == "peanuts")
        {
            result = amount * 1.60;
            Console.WriteLine(result);

        }
    }
    else if (city == "Plovdiv")
    {
        if (product == "coffee")
        {
            result = amount * 0.40;
            Console.WriteLine(result);

        }
        else if (product == "water")
        {
            result = amount * 0.70;
            Console.WriteLine(result);

        }
        else if (product == "beer")
        {
            result = amount * 1.15;
            Console.WriteLine(result);

        }
        else if (product == "sweets")
        {
            result = amount * 1.30;
            Console.WriteLine(result);

        }
        else if (product == "peanuts")
        {
            result = amount * 1.50;
            Console.WriteLine(result);

        }
    }
    else if (city == "Varna")
    {
        if (product == "coffee")
        {
            result = amount * 0.45;
            Console.WriteLine(result);

        }
        else if (product == "water")
        {
            result = amount * 0.70;
            Console.WriteLine(result);

        }
        else if (product == "beer")
        {
            result = amount * 1.10;
            Console.WriteLine(result);

        }
        else if (product == "sweets")
        {
            result = amount * 1.35;
            Console.WriteLine(result);

        }
        else if (product == "peanuts")
        {
            result = amount * 1.55;
            Console.WriteLine(result);

        }
        else
        {
            Console.WriteLine("Invalid");
        }
    }

Answer 1

您将 city 转换为小写，然后使用大写首字母进行比较!那不会有好结果。

即你需要

if (city == "sofia")

等等

您的逐行调试器可用于验证这一点。请花一些时间学习如何使用它。调试比能够键入代码更重要。