c# - 无法从 double 转换为十进制错误

Question

对于此作业，我需要使用 BankAccount 程序做一些事情，但首先我需要复制让示例运行。我已经完全按照下面的屏幕截图从作业表中复制了代码，但我收到如下所示的错误。

Error   2   Argument 1: cannot convert from 'double' to 'decimal' Line 13 Column 51
Error   1   The best overloaded method match for 'BankAccount.BankAccount.BankAccount(decimal)' has some invalid arguments Line 13 Column 35    
Error   4   Argument 1: cannot convert from 'double' to 'decimal' Line 13 Column 30 
Error   3   The best overloaded method match for 'BankAccount.BankAccount.Withdraw(decimal)' has some invalid arguments Line 18 Column 13   

我不知道是什么导致了这些错误，因为我认为我没有使用过 double 一次，而且非常快速地谷歌错误并没有帮助我。

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

namespace BankAccount
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create Bank Account & Print Balance
            BankAccount account = new BankAccount(142.50);
            Console.WriteLine("Account Balance is: " + account.ToString());

            // Withdraw £30.25
            Console.WriteLine("Withdrawing £30.25");
            account.Withdraw(30.25);

            // Print balance again
            Console.WriteLine("Account Balance is: " + account.ToString());
        }
    }

.

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

namespace BankAccount
{
   public class BankAccount
    {
       private decimal _balance;

       public decimal Balance
       {
           get { return _balance; }
           private set { _balance = value; }
       }

       //Constructor: Constructs a new Bank Account with 0 balance
       public BankAccount()
       {
           Balance = 0;
       }

       //Constructor: Constructs a new Bank Account with the specified balance
       public BankAccount(decimal balance)
       {
           Balance = balance;
       }

       //Deposits the specified amount into the Bank Account
       public void Deposit(decimal amount)
       {
           Balance += amount;
       }

       //Withdraws the specified amount from the Bank Account
       public void Withdraw(decimal amount)
       {
           Balance -= amount;
       }

       //ToString Override
       public override string ToString()
       {
           return string.Format("{0}: Balance = {1}", "BankAccount", Balance);

       }
    }
}

Answer 1

这里:

 BankAccount account = new BankAccount(142.50);

您正在传递 double 文字 142.50。然而，BankAccount 需要一个 decimal literal相反:

 BankAccount account = new BankAccount(142.50m);

注意数字后面的m。