Question

我的代码首先使用用户输入的“ s”或“ k”或“ c”来显示价格。用户输入硬币价值以降低该价格。当用户输入“ s”和第一个硬币值时，我的代码起作用了，但是在第四次输入后它就关闭了，我不确定为什么。

我尝试了ReadKey和Console.ReadLine，但是我不确定从这里去哪里

namespace VendingMachine
{
    class Program
    {
        static void Main(string[] args)
        {
            //Gives user necessary info to operate vending machine
            Console.WriteLine("Welcome to vending machine.");
            Console.WriteLine("We offer you (s)oda, coo(k)ies, and (c)hips");
            Console.WriteLine("Please select the product you want to purchase:");
            string userselection = Console.ReadLine();


            if (userselection == "s")
            {
                //Generates a random number between 0 and 5 using the random class
                Random rn = new Random();
                int randomnumber = rn.Next(1, 5);
                double lottery = randomnumber * 10;
                Console.WriteLine("Congratulations! You win a coupon with " + lottery + " cents.");

                //soda price after lottery 
                double sodaprice = 100 - lottery;
                Console.WriteLine("You only need to pay " + sodaprice + " cents");
                Console.WriteLine("Please insert a coin of 5, 10, or 25:");
                string coininput = Console.ReadLine();
                double coin = Convert.ToDouble(coininput);


                while (coin > 0)
                {
                    if (coin == 25)
                    {
                        double sodapricecoins = sodaprice - coin;
                        Console.WriteLine("You still owe " + sodapricecoins + " cents.");
                        Console.WriteLine("Please insert a coin of 5, 10, or 25:");
                        break;
                    }
                    else if (coin == 10)
                    {
                        double sodapricecoins = sodaprice - coin;
                        Console.WriteLine("You still owe " + sodapricecoins + " cents.");
                        Console.WriteLine("Please insert a coin of 5, 10, or 25:");
                        break;
                    }
                    else if (coin == 5)
                    {
                        double sodapricecoins = sodaprice - coin;
                        Console.WriteLine("You still owe " + sodapricecoins + " cents.");
                        Console.WriteLine("Please insert a coin of 5, 10, or 25:");
                        break;
                    }
                }

            }
}
}
}

程序应该一直运行，直到达到0或负数为止，我知道我还没有这个部分。

Answer 1

第一件事是删除三个if中的 break ，但是如果您注意到三个if包含相同的代码。根本不需要它们。

第二点是要有一种退出循环的方法。如果用户输入的硬币金额等于或小于零，则可能是零。

第三点是询问循环中的硬币值，进行数学运算，然后确定是否要继续循环或停止循环。

Console.WriteLine("You only need to pay " + sodaprice + " cents");
// To force to start the loop, we ask the value inside the loop
double coin = 1d;

// We should reach zero or less starting from the initial price (minus lottery)  
double amountDue = sodaprice;
while (coin > 0)
{
    Console.WriteLine("Please insert a coin of 5, 10, or 25:");
    string coininput = Console.ReadLine();

    // use tryparse when trying to convert user input in numbers.
    // tryparse returns true if the input is a number without raising exceptions
    if(double.TryParse(coininput, out coin))
    {

       // Decrement the amount to pay with the user input
       amountDue -= coin;

       // Decide for a message and continue the loop or stop 
        if(amountDue > 0)
            Console.WriteLine("You still owe " + amountDue + " cents.");
        else
            break;
    }
}

Answer 2

如果您希望该程序连续运行直到苏打价格达到0或为负数，请尝试使用此代码，但当您使用硬币> 0的条件进行while循环时，请继续操作，直到用户键入零或负数。

//Gives user necessary info to operate vending machine
        Console.WriteLine("Welcome to vending machine.");
        Console.WriteLine("We offer you (s)oda, coo(k)ies, and (c)hips");
        Console.WriteLine("Please select the product you want to purchase:");
        string userselection = Console.ReadLine();


        if (userselection == "s")
        {
            //Generates a random number between 0 and 5 using the random class
            double lottery = new Random().Next(1, 5) * 10;
            Console.WriteLine("Congratulations! You win a coupon with " + lottery + " cents.");

            //soda price after lottery 
            double sodaprice = 100 - lottery;
            Console.WriteLine("You only need to pay " + sodaprice + " cents");

            double coin;
            do
            {
                Console.WriteLine("Please insert a coin of 5, 10, or 25:");
                if (double.TryParse(Console.ReadLine(), out coin))
                {
                    if (coin == 25 || coin == 10 || coin == 5)
                    {
                        sodaprice -= coin;
                        Console.WriteLine(sodaprice > 0 ? "You still owe " + sodaprice + " cents." : "Finish...");

                    }
                }
            } while (sodaprice > 0);

        }
        Console.ReadLine();

代码应该包括所有用户输入，但在第三次输入后停止

2 个答案: