C# 操作用户输入（数学）

我用的是C。我试图允许用户输入一个数值（即：你想要多少？），然后取那个值并计算税额和总额。我不知道该怎么做，不知道是否有人能给我看？我当前的脚本如下：

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 abbreviation:");
            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();    
        }
    }
}

---

只是一点建议，您可以在Console.WriteLine（）中包含非字符串变量，如：

这是大多数专业开发人员所做的。不需要复杂的C/C++风格的解析

而且，您似乎没有声明变量o和p。试试这个：

双o=转换为双（n*0.9）

或

---

双o=（双）（n*0.9）

您应该使用

int ordered = int.Parse(NumberOrdered);

---

并继续使用该整数进行计算。

因为用户以字符串形式输入信息，所以您应该将排序的数字转换为整数。此外，为了保留小数，您需要将数字存储为数字的两倍

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");

---

你忘了声明一些变量和赋值​​.

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();
}

---

希望这有帮助

您的程序无法编译。永远不要说你的程序“不起作用”。解释你期望发生的事情和实际发生的事情。什么是

m

？我看不出它的定义。这是一个相当长的程序。也许您可以使用s等删除所有不必要的东西，例如

？看起来您正在尝试使用
string
s进行数学运算。他们不喜欢那样。将它们转换为
int
，
float
或其他任何形式。这是一个相当大的概括。。。没有理由引导人们远离字符串格式的方法。有很多。这是一种更直观的编码方式，更容易理解并减少人为错误的可能性，特别是在处理不同类型的多个变量时。糟糕的建议。没有回答这个问题。
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();
}