计算板率

Question

我想使用C#根据板材计算电费，如下表所示

 SlabFrom    SlabTo      Rate

   0           100         5.00
  101          500         10.00
  501          Null        15.00

板数可以更改，需要最佳解决方案来计算总成本

根据总使用量。如果总使用量为1,000，则应计算：

(100 X 5) + (400 X 10) + (500 X 15) = 12,000

public class Cost
{
    public decimal  SlabFrom { get; set; }  

    public decimal SlabTo { get; set; }  

    public bool SlabHour { get; set; }

    public decimal RatePerUnit { get; set; }
}

        var rates = new List<Cost>
        {
            new Cost()
            {
                SlabFrom = 0,
                SlabTo = 100,
                RatePerUnit = 5
            },
            new Cost()
            {
                SlabFrom = 101,
                SlabTo = 500,
                RatePerUnit = 10
            },
            new Cost()
            {
                SlabFrom = 501,
                SlabTo = 1000,
                RatePerUnit = 15
            },
            new Cost()
            {
                SlabFrom = 1001,
                SlabTo = 1500,
                RatePerUnit = 20
            }
        };

Answer 1

如果你只想要前3个

int usage = 503;
int total = usage < 100 ? usage * 5 : 500 + (usage < 500 ? (usage - 100) * 10 : 4000 + (usage - 500) * 15);
 //4545

如果你想要一个更通用的答案

顺便说一句，我用你的成本类来测试这个

decimal used = 1000;
decimal LastSlabto = 0;
decimal total = 0;

foreach (Cost rate in rates)
{
   if (used > rate.SlabTo - LastSlabto)
      total += (rate.SlabTo - LastSlabto) * rate.RatePerUnit;
   else
   {
      total += used * rate.RatePerUnit;
      used = 0;
      break;
   }
   used -= rate.SlabTo - LastSlabto;
   LastSlabto = rate.SlabTo;             
} 

Answer 2

您可以这样做：

rates.TakeWhile(item => item.SlabFrom totalUsage)
     .Sum(item => (double)((item.SlabTo > totalUsage ? totalUsage : item.SlabTo) - item.SlabFrom) * item.RatePerUnit);

Answer 3

尝尝这个

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

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("SlabFrom", typeof(int));
            dt.Columns.Add("SlabTo", typeof(int));
            dt.Columns["SlabTo"].AllowDBNull = true;
            dt.Columns.Add("Rate", typeof(double));

            dt.Rows.Add(new object[] {0,100,5.00});
            dt.Rows.Add(new object[] {100,500,10.00});
            dt.Rows.Add(new object[] {501,null,15.00});

            int usage = 1500;

            double cost = 0;
            foreach(DataRow row in dt.AsEnumerable())
            {
                if(usage > 0)
                {
                    if((row.Field<int?>("SlabTo") == null) || (usage < row.Field<int>("SlabTo")))
                    {
                        cost += usage * row.Field<double>("Rate");
                        usage = 0;
                    }
                    else
                    {
                         cost += (row.Field<int>("SlabTo") - row.Field<int>("SlabFrom")) * row.Field<double>("Rate");
                         usage -=  (row.Field<int>("SlabTo") - row.Field<int>("SlabFrom"));
                    }
                }
            }
         }
    }

}