如何让这个程序允许输入小数?

Question

我有一个问题，我必须做一个学校的作业。我在处理小数时遇到了麻烦。如果有人能帮我让程序接受小数。它会输出一个小数，但不允许我输入一个。

using System;
    public class Bank_Account
    {
        public static void Main()
        {
            char input, C, D, P, Q;
            double balance;
            Console.WriteLine("Please enter C for Cheque, D for Deposit, P for Print or Q to quit");
            input = Convert.ToChar(Console.ReadLine());
            do
            {
                switch (input)
                {
                    case 'D':
                        Deposit(ref balance);
                        break;
                    case 'P':
                        Print(balance);
                        break;
                    case 'C':
                        Cheque(ref balance);
                        break;
                    default:
                        Console.WriteLine("{0} is not a valid choice", input);
                        break;
                }
            } while (input != 'Q');
        }
        public static void Deposit(ref double balance)
        {
            double deposit;
            Console.WriteLine("Enter the amount you want to deposit: ");
            deposit = Convert.ToInt32(Console.ReadLine());
            if (deposit > 1000)
            {
                deposit = deposit*1.02;
            }
            else
            {
                deposit = deposit;
            }
            balance = +deposit;
        }

        public static void Cheque(ref double balance)
        {
            var tempBalance = balance;
            double deduction;
            const double fee = 1;

            do
            {
                Console.WriteLine("Enter the amount of the cheque: ");
                deduction = Convert.ToInt32(Console.ReadLine());
            } while (deduction < 0);

            tempBalance = balance - deduction - fee;
            if (tempBalance < 0)
            {
                Console.Write("Not enough money in the account");
            }
            else
            {
                balance = tempBalance;
            }
        }

        public static void Print(double balance)
        {
            Console.WriteLine("Your current balance is {0.00}", balance);
        }
    }

Answer 1

修改如下:

deposit = Convert.ToInt32(Console.ReadLine());

:

deposit = Convert.ToDouble(Console.ReadLine());

，因为你读的不是整型，而是双精度。像另一个答案中建议的那样使用TryParse会更好。此外，如果你需要精度，也许你应该使用十进制而不是双精度，但如果精度不那么重要，则使用双精度。

Answer 2

要转换为整型，像这样修改

        do
        {
            Console.WriteLine("Enter the amount of the cheque: ");
            deduction = Convert.ToDouble(Console.ReadLine());
        } 

Answer 3

Try This:

double deposit;
double.TryParse(Console.ReadLine(),out deposit);

Answer 4

deposit = Double.Parse(Console.ReadLine());