处理用户输入（Mathmatical）

Question

我是C＃的2周nube。我试图让用户输入一个数值（IE：你想要多少？），然后取这个值并计算税和总额。我无法弄清楚如何做到这一点，并想知道是否有人可以告诉我？谢谢，我现在的脚本是波纹管：

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

namespace ConsoleApplication1 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      Console.WriteLine("Welcome to Infinate Happiness Ranch.\nPlease enter your order information bellow. "); 

      Console.WriteLine(); 

      Console.WriteLine("Please enter your first and last name:"); 
      string FirstName = Console.ReadLine(); 

      Console.WriteLine("Please enter your street address:"); 
      string Address = Console.ReadLine(); 

      Console.WriteLine("Please enter your city:"); 
      string City = Console.ReadLine(); 

      Console.WriteLine("Please enter your two letter state abreviation:"); 
      string StateCode = Console.ReadLine(); 

      Console.WriteLine("Please enter your zip code:"); 
      string ZipCode = Console.ReadLine(); 

      Console.WriteLine("Please enter the number of Tribbles \nyou wish to purchase for $29.99 plus tax"); 
      string NumberOrdered = Console.ReadLine(); 

      Console.WriteLine("Invoice \nName {0}", FirstName); 
      Console.WriteLine("Address {0}", Address); 
      Console.WriteLine("City {0}", City); 
      Console.WriteLine("StateCode {0}", StateCode); 
      Console.WriteLine("ZipCode {0}", ZipCode); 
      Console.WriteLine("NumberOrdered {0}", NumberOrdered); 
      // PROGRAM WORKS UNTIL HERE. 
      NumberOrdered = m; 
      TotalBeforeTax = m * 29.99; //'n' is total b4 tax 
      o = n * 0.9;// 'o' is total tax due 
      p = o + n; // 'p' is total due 

      Console.WriteLine("Your total is {0} {1}", n); 
      Console.WriteLine("Your tax is {0}", o); 
      Console.WriteLine("Your total charge is {0}", p); 
      Console.WriteLine("Thank you for your order"); 
      Console.WriteLine(); 

      //Console.WriteLine("Name:" + FirstName); 
      Console.Read();  
     } 
    } 
} 

Answer 1

只是一些建议，您可以在Console.WriteLine非字符串变量（），如：

Console.WriteLine("Your tax is " + o); 

这是最专业的开发商做。不需要复杂的C/C++风格的解析。

另外，你似乎没有声明变量o和p。试试这个：

double o = Convert.toDouble（n * 0.9）;

或

double o =（double）（n * 0.9）;

Answer 2

你应该解析字符串

int ordered = int.Parse(NumberOrdered); 

，并继续与这个整数来计算。

Answer 3

由于用户以字符串形式输入信息，因此应该将订购的数字转换为整数。另外，为了保留小数点，您需要将数字存储为诸如此类数量的双精度数。

int numOrdered = Convert.ToInt32(NumberOrdered); 
double TotalBeforeTax = numOrdered * 29.99; 

double beforeTax = TotalBeforeTax * 0.9; 
double afterTax = beforeTax + TotalBeforeTax; 

Console.WriteLine("Your total is {0}", TotalBeforeTax); 
Console.WriteLine("Your tax is {0}", beforeTax); 
Console.WriteLine("Your total charge is {0}", afterTax); 
Console.WriteLine("Thank you for your order"); 

Answer 4

您忘记声明一些变量并分配一些值。

试试这个：

static float m; 
static float n; 
static float o; 
static float p; 
static float TotalBeforeTax; 
static void Main(string[] args) 
{ 
    Console.WriteLine("Welcome to Infinate Happiness Ranch.\nPlease enter your order information bellow. "); 
    Console.WriteLine(); 

    Console.WriteLine("Please enter your first and last name:"); 
    string FirstName = Console.ReadLine(); 

    Console.WriteLine("Please enter your street address:"); 
    string Address = Console.ReadLine(); 

    Console.WriteLine("Please enter your city:"); 
    string City = Console.ReadLine(); 

    Console.WriteLine("Please enter your two letter state abreviation:"); 
    string StateCode = Console.ReadLine(); 

    Console.WriteLine("Please enter your zip code:"); 
    string ZipCode = Console.ReadLine(); 

    Console.WriteLine("Please enter the number of Tribbles \nyou wish to purchase for $29.99 plus tax"); 
    string NumberOrdered = Console.ReadLine(); 

    Console.WriteLine("Invoice \nName {0}", FirstName); 
    Console.WriteLine("Address {0}", Address); 
    Console.WriteLine("City {0}", City); 
    Console.WriteLine("StateCode {0}", StateCode); 
    Console.WriteLine("ZipCode {0}", ZipCode); 
    Console.WriteLine("NumberOrdered {0}", NumberOrdered); 
    //PROGRAM WORKS UNTIL HERE ? HELP ? ? ? ? ? 
    //NumberOrdered = m; 
    m = float.Parse(NumberOrdered); 
    TotalBeforeTax = m * 29.99f; //'n' is total b4 tax 
    n = TotalBeforeTax; 
    o = n * 0.9f;//'o' is total tax due 
    p = o + n; //'p' is total due 

    Console.WriteLine("Your total is {0}", n); 
    Console.WriteLine("Your tax is {0}", o); 
    Console.WriteLine("Your total charge is {0}", p); 
    Console.WriteLine("Thank you for your order"); 
    Console.WriteLine(); 
    Console.Read(); 
} 

希望这有助于！