這是大二上學期課設的一道題，我當時剛好學習了C#，C#窗體應用程式的介面程式碼和業務程式碼是分開的，這比其他同學使用的C++MFC要方便很多，分享給你，希望對你有幫助。閱讀本文並加以實現的話，需要有一定的C#程式設計基礎，當然，程式碼裡面計算中綴表示式的方法還是值得一看的。
在編輯區它是這樣子的：

注意右側的解決方案資源管理器中的檔案，後面會一個一個粘上來~~~

在看看執行時的效果吧：

如果瞭解C#窗體應用程式，實現起來應該是不會有問題的，我下面就開始貼程式碼了，敲黑板~~~我們的重點在棧和佇列的應用

Form1.cs

using System;
using System.Collections.Generic;
using
 
 System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace 計算器的設計與實現CSharp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        string
 
 input="";
        /// <summary>
        /// 監聽輸入函式
        /// </summary>
        /// <param name="c">輸入的字元</param>
        void Input(char c)
        {
            input += c;
        }
        /// <summary>
        /// 顯示函式
        /// </summary>
        void ShowMessage()
        {
            txtBox.Text = input;
        }

        #region
 
 監聽輸入
        private void btn1_Click(object sender, EventArgs e)
        {
            Input('1');
            ShowMessage();
        }

        private void btn2_Click(object sender, EventArgs e)
        {
            Input('2');
            ShowMessage();
        }

        private void btn3_Click(object sender, EventArgs e)
        {
            Input('3');
            ShowMessage();
        }

        private void btn4_Click(object sender, EventArgs e)
        {
            Input('4');
            ShowMessage();
        }

        private void btn5_Click(object sender, EventArgs e)
        {
            Input('5');
            ShowMessage();
        }

        private void btn6_Click(object sender, EventArgs e)
        {
            Input('6');
            ShowMessage();
        }

        private void btn7_Click(object sender, EventArgs e)
        {
            Input('7');
            ShowMessage();
        }

        private void btn8_Click(object sender, EventArgs e)
        {
            Input('8');
            ShowMessage();
        }

        private void btn9_Click(object sender, EventArgs e)
        {
            Input('9');
            ShowMessage();
        }

        private void btn0_Click(object sender, EventArgs e)
        {
            Input('0');
            ShowMessage();
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            Input('+');
            ShowMessage();
        }

        private void btnSubtruct_Click(object sender, EventArgs e)
        {
            Input('-');
            ShowMessage();
        }

        private void btnRide_Click(object sender, EventArgs e)
        {
            Input('x');
            ShowMessage();
        }

        private void btnRemove_Click(object sender, EventArgs e)
        {
            Input('÷');
            ShowMessage();
        }

        private void btnDot_Click(object sender, EventArgs e)
        {
            Input('.');
            ShowMessage();
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            input = "";
            txtBox.Text = "";
            ShowMessage();
            txtBox.ReadOnly = false;
            btnEqual.Enabled = true;
        }
        #endregion

        /// <summary>
        /// 判斷運算優先順序
        /// </summary>
        /// <param name="sign"></param>
        /// <returns></returns>
        private int GetSignYouXianJi(char sign)  // get sign priority
        {
            switch (sign)
            {
                case '+':
                case '-':
                    return 1;
                case 'x':
                case '÷':
                    return 2;
            }
            return -1;
        }

        /// <summary>
        /// 分析字尾表示式
        /// </summary>
        /// <param name="obj">使用者輸入的資訊</param>
        /// <returns></returns>
        private char HouZhuiBiaoDaShi(string obj)
        {
            if (obj == "+")
            {
                return '+';
            }
            else if (obj == "-")
            {
                return '-';
            }
            else if (obj == "x")
            {
                return 'x';
            }
            else if (obj == "÷")
            {
                return '÷';
            }
            else                
            {
                return '0';
            }
        }


        /// <summary>
        /// 計算表示式的結果
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnEqual_Click(object sender, EventArgs e)
        {
            btnEqual.Enabled = false;//避免多次輸入"="帶來的異常

            Stack<double> tempStack = new Stack<double>();                  // 運算棧
            Queue<string> houZhuiBiaoDaShiQueue = new Queue<string>();     // 儲存字尾表示式的佇列
            Stack<char> signStack = new Stack<char>();                      // 運算子棧

            string tempStr = "";                                            // 臨時記錄輸入的數字或小數點
            int objType;
            double tempDouble;

            try
            {
                #region 中綴表示式轉字尾表示式
                for (int i = 0; i < input.Length; i++)
                {
                    if (input[i] <= '9' && input[i] >= '0' || input[i] == '.')  //找出運算數
                    {
                        tempStr += input[i];
                    }
                    else
                    {
                        if (tempStr.Length > 0)             //如果符號前存在數字，則將數字新增到houZhuiBiaoDaShiQueue隊尾
                        {
                            houZhuiBiaoDaShiQueue.Enqueue(tempStr);
                            tempStr = "";
                        }
                        if (signStack.Count == 0)           //運算子棧為空，該運算子直接入棧
                        {
                            signStack.Push(input[i]);
                        }
                        else                                //運算子棧不為空，需要判斷運算子的優先順序
                        {
                            #region 判斷運算優先順序
                            if (GetSignYouXianJi(input[i]) > GetSignYouXianJi(signStack.Peek()))
                            {
                                signStack.Push(input[i]);
                            }
                            else
                            {
                                while (true)
                                {
                                    houZhuiBiaoDaShiQueue.Enqueue(Convert.ToString(signStack.Pop()));
                                    if (signStack.Count == 0 || GetSignYouXianJi(input[i]) > GetSignYouXianJi(signStack.Peek()))
                                        break;
                                }
                                signStack.Push(input[i]);
                            }
                            #endregion
                        }
                    }
                }   // end for

                if (tempStr.Length > 0)   //將最後一個運算數新增到houZhuiBiaoDaShiQueue隊尾
                {
                    houZhuiBiaoDaShiQueue.Enqueue(tempStr);
                    tempStr = "";
                }
                while (signStack.Count > 0)//將所有運算子依次新增到隊尾，形成字尾表示式
                {
                    houZhuiBiaoDaShiQueue.Enqueue(Convert.ToString(signStack.Pop()));
                }
                #endregion

                signStack.Clear();
                tempStr = "";

                #region 計算字尾表示式

                while (houZhuiBiaoDaShiQueue.Count > 0)
                {
                    objType = HouZhuiBiaoDaShi(houZhuiBiaoDaShiQueue.Peek());
                    switch (objType)
                    {
                        case '0':                 // 如果是運算數，則直接入棧（並在字尾表示式佇列中移除該運算數）
                            tempStack.Push(Convert.ToDouble(houZhuiBiaoDaShiQueue.Dequeue()));
                            break;
                        case '+':
                            houZhuiBiaoDaShiQueue.Dequeue();//在後綴表示式佇列中移除該運算子
                            tempStack.Push(tempStack.Pop() + tempStack.Pop());
                            break;
                        case '-':
                            houZhuiBiaoDaShiQueue.Dequeue();
                            tempDouble = tempStack.Pop();//提取出減數
                            tempStack.Push(tempStack.Pop() - tempDouble);
                            break;
                        case 'x':
                            houZhuiBiaoDaShiQueue.Dequeue();
                            tempStack.Push(tempStack.Pop() * tempStack.Pop());
                            break;
                        case '÷':
                            houZhuiBiaoDaShiQueue.Dequeue();
                            tempDouble = tempStack.Pop();//提取出除數
                            if (tempDouble != 0)
                            {
                                tempStack.Push(tempStack.Pop() / tempDouble);
                            }
                            else
                            {
                                MessageBox.Show("Error: 0是被除數！");
                            }
                            break;
                        default:
                            MessageBox.Show("未知錯誤！");
                            break;
                    }
                }
                #endregion

                input += "=" + Convert.ToString(tempStack.Pop());

                ShowMessage();
                txtBox.ReadOnly = true;
            }
            catch (Exception)
            {
                MessageBox.Show("請輸入正確的運算式！");
                throw;
            }
        }
    }
}

當時我正好看了設計模式這本書，下面的程式碼有點走架構風，不過感覺也不影響理解

Operation.cs

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

namespace 計算器的設計與實現CSharp
{
    public class Operation:Form1
    {
        public double NumberA { get; set; }
        public double NumberB { get; set; }
        public virtual double GetResult()
        {
            double result = 0;
            return result;
        }

    }
}

OperationAdd.cs

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

namespace 計算器的設計與實現CSharp
{
    public class OperationAdd : Operation
    {
        public override double GetResult()
        {
            return NumberA + NumberB;
        }

    }
}

OperationRemove.cs

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

namespace 計算器的設計與實現CSharp
{
   public class OperationRemove:Operation
    {
        public override double GetResult()
        {
            if (NumberB!=0.0)
            {
                return NumberA / NumberB;
            }
            else
            {
                return 0;
            }
        }

    }
}

OperationRide.cs

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

namespace 計算器的設計與實現CSharp
{
    public class OperationRide:Operation
    {
        public override double GetResult()
        {
            return NumberA * NumberB;
        }

    }
}

OperationSubtruct.cs

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

namespace 計算器的設計與實現CSharp
{
    public class OperationSubtruct : Operation
    {
        public override double GetResult()
        {
            return NumberA - NumberB;
        }

    }
}

自我感覺註釋寫得很清楚了，希望對你有幫助~~~