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C# 我的第一台计算器需要帮助吗

c#

C# 我的第一台计算器需要帮助吗,c#,calculator,C#,Calculator,所以我刚开始学习编码，已经学了大约一周了。我想试着做一个计算器，可以+和-但是我不知道如何让用户选择他想要使用的东西，有人可以帮我吗？ 这是代码 int x; int y; Console.WriteLine("Welcome to my calculator program!"); Console.WriteLine("This calculator for now can only do + and -"); C

所以我刚开始学习编码，已经学了大约一周了。我想试着做一个计算器，可以+和-但是我不知道如何让用户选择他想要使用的东西，有人可以帮我吗？ 这是代码

        int x;
        int y;
        Console.WriteLine("Welcome to my calculator program!");
        Console.WriteLine("This calculator for now can only do + and -");
        Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

        Console.WriteLine("pls write in you x");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("pls write in your y");
        y = Convert.ToInt32(Console.ReadLine());

        if (x > y)
        {
            Console.WriteLine("you chose to use minus");
            int sum = x - y;
            Console.WriteLine("result: {0}", sum);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }
        else
        {
            Console.WriteLine("you chose to use plus");
            int sum1 = x + y;
            Console.WriteLine("result: {0}", sum1);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }


     }
}
}
正如你所看到的，如果x i小于y，则使用+x，如果x大于y，则使用-x。我知道如何让它工作的唯一方法。

欢迎来到计算机程序的伟大世界。 应用程序开发就是为用户提供选项并动态处理他/她的请求。 因此，正如您获得x和y的值一样，您可能从用户处获得运算符。一个简单的例子如下：

int x;
int y;
Console.WriteLine("Welcome to my calculator program!");
Console.WriteLine("This calculator for now can only do + and -");
Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

Console.WriteLine("pls write in you x");
x = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("pls write in your y");
y = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("insert operator");
string o = Console.ReadLine();

if (o=="-")
{
    Console.WriteLine("you chose to use minus");
    int sum = x - y;
    Console.WriteLine("result: {0}", sum);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else if (o=="+")
{
    Console.WriteLine("you chose to use plus");
    int sum1 = x + y;
    Console.WriteLine("result: {0}", sum1);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else
{
    Console.WriteLine("the operator is not recognized");
}

class Program
{
    static void Main(string[] args)
    {
        CSharpReplAsync().Wait();

    }

    private static async Task CSharpReplAsync()
    {
        Console.WriteLine("C# Math REPL");
        Console.WriteLine("You can use any method from System.Math");

        var options = ScriptOptions.Default
            .AddImports("System", "System.Console", "System.Math");

        var state = await CSharpScript.RunAsync("WriteLine(\"Hello from Roslyn\")", options);

        while (true)
        {
            Console.Write("> ");
            string expression = Console.ReadLine();
            if (string.IsNullOrEmpty(expression))
                break;
            try
            {
                state = await state.ContinueWithAsync(expression, options);
                if (state.ReturnValue != null)
                    Console.WriteLine(state.ReturnValue);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}
如果你觉得答案有用，请在上面标出。

欢迎来到计算机程序的伟大世界。 应用程序开发就是为用户提供选项并动态处理他/她的请求。 因此，正如您获得x和y的值一样，您可能从用户处获得运算符。一个简单的例子如下：

int x;
int y;
Console.WriteLine("Welcome to my calculator program!");
Console.WriteLine("This calculator for now can only do + and -");
Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

Console.WriteLine("pls write in you x");
x = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("pls write in your y");
y = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("insert operator");
string o = Console.ReadLine();

if (o=="-")
{
    Console.WriteLine("you chose to use minus");
    int sum = x - y;
    Console.WriteLine("result: {0}", sum);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else if (o=="+")
{
    Console.WriteLine("you chose to use plus");
    int sum1 = x + y;
    Console.WriteLine("result: {0}", sum1);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else
{
    Console.WriteLine("the operator is not recognized");
}

class Program
{
    static void Main(string[] args)
    {
        CSharpReplAsync().Wait();

    }

    private static async Task CSharpReplAsync()
    {
        Console.WriteLine("C# Math REPL");
        Console.WriteLine("You can use any method from System.Math");

        var options = ScriptOptions.Default
            .AddImports("System", "System.Console", "System.Math");

        var state = await CSharpScript.RunAsync("WriteLine(\"Hello from Roslyn\")", options);

        while (true)
        {
            Console.Write("> ");
            string expression = Console.ReadLine();
            if (string.IsNullOrEmpty(expression))
                break;
            try
            {
                state = await state.ContinueWithAsync(expression, options);
                if (state.ReturnValue != null)
                    Console.WriteLine(state.ReturnValue);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}
如果您觉得答案有用，请标记它。

首先让我感谢您的尝试，现在我将添加一些注释来改进代码片段。您可以使用
int.TryParse
进行转换，这将帮助您处理
FormatExceptions
，然后从用户处获取运算符，并使用切换案例识别它，并根据用户输入执行操作

将此代码作为参考，不要复制和粘贴

int firstNumber, secondNumber;
Console.WriteLine("pls write in you x");
if (!int.TryParse(Console.ReadLine(), out firstNumber))
{
    Console.WriteLine("Sorry this is not an integer, 0 will be assigned");
}
Console.WriteLine("pls write in your y");
if (!int.TryParse(Console.ReadLine(), out secondNumber))
{
    Console.WriteLine("Sorry this is not an integer, 0 will be assigned");
}

/ Now you have two numbers to perform the operation
// You can now prompt the user to enter the operator
Console.WriteLine("pls enter the operator");
char operatorSign = Console.ReadKey().KeyChar;
switch (operatorSign)
{
    case '+' :
        Console.WriteLine("Result {0} + {1} = {2}", firstNumber, secondNumber, firstNumber + secondNumber);
        break;
    case '_':
        Console.WriteLine("Result {0} - {1} = {2}", firstNumber, secondNumber, firstNumber - secondNumber);
        break;
    case '*':
        Console.WriteLine("Result {0} * {1} = {2}", firstNumber, secondNumber, firstNumber * secondNumber);
        break;
    default:             
        Console.WriteLine("Sorry we are not providing this operation");
        break;
}
Console.ReadKey();
首先让我感谢您的尝试，现在我将添加一些注释来改进代码段。您可以使用
int.TryParse
进行转换，这将帮助您处理
FormatExceptions
，然后从用户处获取运算符，并使用切换案例识别它，并根据用户输入执行操作

将此代码作为参考，不要复制和粘贴

int firstNumber, secondNumber;
Console.WriteLine("pls write in you x");
if (!int.TryParse(Console.ReadLine(), out firstNumber))
{
    Console.WriteLine("Sorry this is not an integer, 0 will be assigned");
}
Console.WriteLine("pls write in your y");
if (!int.TryParse(Console.ReadLine(), out secondNumber))
{
    Console.WriteLine("Sorry this is not an integer, 0 will be assigned");
}

/ Now you have two numbers to perform the operation
// You can now prompt the user to enter the operator
Console.WriteLine("pls enter the operator");
char operatorSign = Console.ReadKey().KeyChar;
switch (operatorSign)
{
    case '+' :
        Console.WriteLine("Result {0} + {1} = {2}", firstNumber, secondNumber, firstNumber + secondNumber);
        break;
    case '_':
        Console.WriteLine("Result {0} - {1} = {2}", firstNumber, secondNumber, firstNumber - secondNumber);
        break;
    case '*':
        Console.WriteLine("Result {0} * {1} = {2}", firstNumber, secondNumber, firstNumber * secondNumber);
        break;
    default:             
        Console.WriteLine("Sorry we are not providing this operation");
        break;
}
Console.ReadKey();
有各种可能的方法来完成你的要求。其中最简单的是要求用户输入操作员进行相应的操作：

下面是相同的代码：

using System.IO;
using System;

class Program
{
    static void Main()
    {
        int x;
        int y;


        Console.WriteLine("Welcome to my calculator program!");
        Console.WriteLine("This calculator for now can only do + and -");

        // Reads x and y from console.
        Console.WriteLine("Enter x :");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("Enter y :");
        y = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Enter operator for corresponding operation on x and y.\nSupported operations x - y and x + y");
        string inputOpr = Console.ReadLine(); // Stores operation to perform

        // Compares input operator to perform operation.
        if (inputOpr == "-"){
            Console.WriteLine("you chose to use minus");
            int result = x - y;
            Console.WriteLine("Result: {0}", result);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }

        else if (inputOpr == "+"){
            Console.WriteLine("you chose to use plus");
            int result = x + y;
            Console.WriteLine("Result: {0}", result);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }
        else{
            Console.WriteLine("Invalid Input");
        }
     }
}
有各种可能的方法来完成你的要求。其中最简单的是要求用户输入操作员进行相应的操作：

下面是相同的代码：

using System.IO;
using System;

class Program
{
    static void Main()
    {
        int x;
        int y;


        Console.WriteLine("Welcome to my calculator program!");
        Console.WriteLine("This calculator for now can only do + and -");

        // Reads x and y from console.
        Console.WriteLine("Enter x :");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("Enter y :");
        y = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Enter operator for corresponding operation on x and y.\nSupported operations x - y and x + y");
        string inputOpr = Console.ReadLine(); // Stores operation to perform

        // Compares input operator to perform operation.
        if (inputOpr == "-"){
            Console.WriteLine("you chose to use minus");
            int result = x - y;
            Console.WriteLine("Result: {0}", result);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }

        else if (inputOpr == "+"){
            Console.WriteLine("you chose to use plus");
            int result = x + y;
            Console.WriteLine("Result: {0}", result);
            Console.WriteLine("Press a key to exit");
            Console.ReadLine();
        }
        else{
            Console.WriteLine("Invalid Input");
        }
     }
}
你可以这样走

    static void Main(string[] args)
    {
        int x;
        int y;
        Console.WriteLine("Welcome to my calculator program!");
        Console.WriteLine("This calculator for now can only do + and -");
        Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

        Console.WriteLine("pls write in you x");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("pls write in your y");
        y = Convert.ToInt32(Console.ReadLine());

        string opt;
        int res;
        do
        {
            Console.Write("Enter your operator [+/-/:/x]:\t");
            opt= Console.ReadLine();
            res = "/+/-/:/x/".IndexOf("/" + opt + "/");

        } while (res == -1);

        double result;
        switch (opt)
        {
            case "+":
                 result= x + y;
                break;
            case "-":
                result = x - y;
                break;
            case ":":
                result = (double)x/(double)y;
                break;
            case "x":
                result = x*y;
                break;

            default:
                result = -9999;
                break;
        }
        Console.WriteLine("\n{0} {1} {2} = {3}", x, opt, y, result);
        Console.ReadLine();

    }

}
你可以这样走

    static void Main(string[] args)
    {
        int x;
        int y;
        Console.WriteLine("Welcome to my calculator program!");
        Console.WriteLine("This calculator for now can only do + and -");
        Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

        Console.WriteLine("pls write in you x");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("pls write in your y");
        y = Convert.ToInt32(Console.ReadLine());

        string opt;
        int res;
        do
        {
            Console.Write("Enter your operator [+/-/:/x]:\t");
            opt= Console.ReadLine();
            res = "/+/-/:/x/".IndexOf("/" + opt + "/");

        } while (res == -1);

        double result;
        switch (opt)
        {
            case "+":
                 result= x + y;
                break;
            case "-":
                result = x - y;
                break;
            case ":":
                result = (double)x/(double)y;
                break;
            case "x":
                result = x*y;
                break;

            default:
                result = -9999;
                break;
        }
        Console.WriteLine("\n{0} {1} {2} = {3}", x, opt, y, result);
        Console.ReadLine();

    }

}
天真的方法（询问用户）已经得到了回答。但实际上，您可能想要实现的是编写一个完整的计算器，用户在其中输入一个字符串，如
2+3
，程序只给出答案。你渴望成为一名翻译

如果您仔细考虑，您将必须执行三项任务：

  • 扫描用户输入，并将其转换为一系列令牌。这是将字符串“2+3”转换为标记系列“值为2的整数”、“加号运算符”、“值为3的整数”
  • 解释标记以计算结果
您对输入施加的约束越多（例如，如您所说，只允许+和-开头），代码就越简单（如果无法根据您设定的规则解释输入，则代码将失败）

如果你想深入挖掘，有很多关于这个主题的资源。我喜欢阅读（作者使用Python，但原理保持不变）

最后，你会发现你正在努力做的很多事情已经实现了。有一些库已经可以解析和计算数学表达式（示例：，）

最后，Roslyn允许您轻松解析任何C#表达式，因此它也可以用于构建一个简单的计算器，如下所示：

int x;
int y;
Console.WriteLine("Welcome to my calculator program!");
Console.WriteLine("This calculator for now can only do + and -");
Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

Console.WriteLine("pls write in you x");
x = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("pls write in your y");
y = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("insert operator");
string o = Console.ReadLine();

if (o=="-")
{
    Console.WriteLine("you chose to use minus");
    int sum = x - y;
    Console.WriteLine("result: {0}", sum);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else if (o=="+")
{
    Console.WriteLine("you chose to use plus");
    int sum1 = x + y;
    Console.WriteLine("result: {0}", sum1);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else
{
    Console.WriteLine("the operator is not recognized");
}

class Program
{
    static void Main(string[] args)
    {
        CSharpReplAsync().Wait();

    }

    private static async Task CSharpReplAsync()
    {
        Console.WriteLine("C# Math REPL");
        Console.WriteLine("You can use any method from System.Math");

        var options = ScriptOptions.Default
            .AddImports("System", "System.Console", "System.Math");

        var state = await CSharpScript.RunAsync("WriteLine(\"Hello from Roslyn\")", options);

        while (true)
        {
            Console.Write("> ");
            string expression = Console.ReadLine();
            if (string.IsNullOrEmpty(expression))
                break;
            try
            {
                state = await state.ContinueWithAsync(expression, options);
                if (state.ReturnValue != null)
                    Console.WriteLine(state.ReturnValue);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}
天真的方法（询问用户）已经得到了回答。但实际上，您可能想要实现的是编写一个完整的计算器，用户在其中输入一个字符串，如
2+3
，程序只给出答案。你渴望成为一名翻译

如果您仔细考虑，您将必须执行三项任务：

  • 扫描用户输入，并将其转换为一系列令牌。这是将字符串“2+3”转换为标记系列“值为2的整数”、“加号运算符”、“值为3的整数”
  • 解释标记以计算结果
您对输入施加的约束越多（例如，如您所说，只允许+和-开头），代码就越简单（如果无法根据您设定的规则解释输入，则代码将失败）

如果你想深入挖掘，有很多关于这个主题的资源。我喜欢阅读（作者使用Python，但原理保持不变）

最后，你会发现你正在努力做的很多事情已经实现了。有一些库已经可以解析和计算数学表达式（示例：，）

最后，Roslyn允许您轻松解析任何C#表达式，因此它也可以用于构建一个简单的计算器，如下所示：

int x;
int y;
Console.WriteLine("Welcome to my calculator program!");
Console.WriteLine("This calculator for now can only do + and -");
Console.WriteLine("If x is highter than y it will do - and if x is lower than y it will do +");

Console.WriteLine("pls write in you x");
x = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("pls write in your y");
y = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("insert operator");
string o = Console.ReadLine();

if (o=="-")
{
    Console.WriteLine("you chose to use minus");
    int sum = x - y;
    Console.WriteLine("result: {0}", sum);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else if (o=="+")
{
    Console.WriteLine("you chose to use plus");
    int sum1 = x + y;
    Console.WriteLine("result: {0}", sum1);
    Console.WriteLine("Press a key to exit");
    Console.ReadLine();
}
else
{
    Console.WriteLine("the operator is not recognized");
}

class Program
{
    static void Main(string[] args)
    {
        CSharpReplAsync().Wait();

    }

    private static async Task CSharpReplAsync()
    {
        Console.WriteLine("C# Math REPL");
        Console.WriteLine("You can use any method from System.Math");

        var options = ScriptOptions.Default
            .AddImports("System", "System.Console", "System.Math");

        var state = await CSharpScript.RunAsync("WriteLine(\"Hello from Roslyn\")", options);

        while (true)
        {
            Console.Write("> ");
            string expression = Console.ReadLine();
            if (string.IsNullOrEmpty(expression))
                break;
            try
            {
                state = await state.ContinueWithAsync(expression, options);
                if (state.ReturnValue != null)
                    Console.WriteLine(state.ReturnValue);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}
也可以从控制台读取字符。然后使用switch case，并根据要求用户写入x和y来执行任务。要求用户写入操作，使用一个开关查找4个操作+，-，*，/中的一个，如果没有选择任何一个，则使用write Console.Log（“无效操作输入”）。另外，当您从控制台获取x和y时，请使用Int或Double-TryParse方法。这将保证用户不能为数字写入E21A，因为您的程序将在当前状态下引发异常。总之，从控制台获取操作，使用TryParse方法，查看如何在发生错误时结束方法的执行（控制台中的无效操作或无效int/decimal）！也可以从控制台读取字符。然后使用switch case，并根据要求用户写入x和y来执行任务。要求用户写入操作，使用一个开关查找4个操作+，-，*，/中的一个，如果没有选择其中任何一个，请写入Console.Log（“无效操作”）