C#带小括号的运算

计算类的封装

jisuan.cs

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

namespace ZY四则运算
{
    public class jisuan
    {
        public Dictionary<char, int> priorities = null;  //优先级

        public void Calculator()    //添加了四种运算符以及四种运算符的优先级
        {
            priorities = new Dictionary<char, int>();
            priorities.Add('#', -1);
            priorities.Add('+', 0);
            priorities.Add('-', 0);
            priorities.Add('*', 1);
            priorities.Add('/', 1);
        }

        const string operators = "+-*/";      //运算符

        public double Compute(double leftNum, double rightNum, char op)  //这是一种方法，用来计算左右两个数的静态方法！
        {
            switch (op)
            {
                case '+': return leftNum + rightNum;
                case '-': return leftNum - rightNum;
                case '*': return leftNum * rightNum;
                case '/': return leftNum / rightNum;
                default: return 0;
            }
        }

        public bool IsOperator(char op)  //每次判断这个字符是否是运算符？
        {
            return operators.IndexOf(op) >= 0;
        }

        public bool IsAssoc(char op)    //返回一个关联符号
        {
            return op == '+' || op == '-' || op == '*' || op == '/';
        }

        public  Queue<object> QueueSort(string expression)   // 队列排序   
        {
            Queue<object> result = new Queue<object>();
            Stack<char> operatorStack = new Stack<char>();   //运算符栈
            operatorStack.Push('#');
            char top, cur, tempChar;                    //top栈顶，current最近的；
            string tempNum;
            for (int i = 0, j; i < expression.Length; )     //取出表达式
            {
                cur = expression[i++];                 //取出表达式的每个字符赋给cur
                top = operatorStack.Peek();        //栈顶元素赋给top此时为"#"

                if (cur == '(')         //将左括号压栈,此时栈顶元素为"("
                {
                    operatorStack.Push(cur);
                }
                else
                {
                    if (IsOperator(cur))       //如果是运算符的话
                    {
                        while (IsOperator(top) && ((IsAssoc(cur) && priorities[cur] <= priorities[top])) || (!IsAssoc(cur) && priorities[cur] < priorities[top]))
                        {
                            result.Enqueue(operatorStack.Pop());     //如果元素为运算符并且优先级小于栈顶元素优先级，出栈
                            top = operatorStack.Peek();      //继续把栈顶元素赋给top
                        }
                        operatorStack.Push(cur);      //把数字压栈
                    }
                    else if (cur == ')')       //将右括号添加到结尾
                    {
                        while (operatorStack.Count > 0 && (tempChar = operatorStack.Pop()) != '(')
                        {
                            result.Enqueue(tempChar);
                        }
                    }
                    else
                    {
                        tempNum = "" + cur;
                        j = i;
                        while (j < expression.Length && (expression[j] == '.' || (expression[j] >= '0' && expression[j] <= '9')))
                        {
                            tempNum += expression[j++];
                        }
                        i = j;
                        result.Enqueue(tempNum);
                    }
                }
            }
            while (operatorStack.Count > 0)
            {
                cur = operatorStack.Pop();
                if (cur == '#') continue;
                if (operatorStack.Count > 0)
                {
                    top = operatorStack.Peek();
                }

                result.Enqueue(cur);
            }

            return result;
        }

        public  double Calucate(string expression)
        {
            try
            {
                var rpn = QueueSort(expression); 
                Stack<double> operandStack = new Stack<double>();
                double left, right;
                object cur;
                while (rpn.Count > 0)
                {
                    cur = rpn.Dequeue();        //出列
                    if (cur is char)            //如果cur为字符的话
                    {
                        right = operandStack.Pop();   //右边的数字出栈
                        left = operandStack.Pop();    //左边的数字出栈
                        operandStack.Push(Compute(left, right, (char)cur));    //此时调用compute方法
                    }
                    else
                    {
                        operandStack.Push(double.Parse(cur.ToString()));      //是数字就压栈
                    }
                }
                return operandStack.Pop();
            }
            catch
            {
                throw new Exception("表达式不正确！");
            }
        }
    }
}

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.Windows.Forms;
using System.IO;

namespace ZY四则运算
{
    public partial class Form1 : Form
    {
        Form2 frm2 = new Form2();
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click_1(object sender, EventArgs e)
        {
            string Express = textBox1.Text;
            frm2.listBox1.Items.Add(Express);
            listBox1.Items.Add(" " + Express + "=");
            textBox1.Clear();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            frm2.ShowDialog();
        }
    }
}

Form2.cs

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

namespace ZY四则运算
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }
        int time = 40; //倒计时
        int Count = 0;
        int right = 0;
        private void Form2_Load(object sender, EventArgs e)
        {
            lblTime.Text = "剩余时间：";
            timer1.Enabled = false;
            timer1.Interval = 1000;
        }      
        private void timer1_Tick(object sender, EventArgs e)
        {
            int tm = time--;
            lblTime.Text = "剩余时间：" + tm.ToString() + "秒";
            if (tm == 0)
            {
                timer1.Enabled = false;
                MessageBox.Show("时间已到", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        private void button1_Click_1(object sender, EventArgs e)
        {
            timer1.Stop();
            MessageBox.Show(label1.Text);
        }
        private void button2_Click_1(object sender, EventArgs e)
        {
            timer1.Start();
        }
        private void button3_Click_1(object sender, EventArgs e)
        {
            sfd.Filter = "(*.txt)|*.txt";
            if (sfd.ShowDialog() == DialogResult.OK)
            {
                string sPath = sfd.FileName;
                FileStream fs = new FileStream(sPath, FileMode.Create);
                StreamWriter sw = new StreamWriter(fs, Encoding.UTF8);
                int iCount = listBox2.Items.Count - 1;
                for (int i = 0; i <= iCount; i++)
                {
                    sw.WriteLine(listBox2.Items[i].ToString());
                }
                sw.Flush();
                sw.Close();
                fs.Close();
            }
        }
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (listBox1.Items.Count > 0)
            {
                textBox1.Text = listBox1.Items[0].ToString();
            }
            else
            {
                MessageBox.Show("答题结束");
            }
        }
        private void textBox2_KeyDown(object sender, KeyEventArgs e)
        {
            jisuan js = new jisuan();
            if (e.KeyCode == Keys.Enter)
            {
                string result = textBox1.Text;
                if (textBox2.Text.Trim() == string.Empty)            //去除空格之后，如果没答题给出提示。
                {
                    MessageBox.Show("您尚未答题", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    return;
                }
                Count++;
                if (textBox2.Text ==js.Calucate(result).ToString())   //直接调用Calucate这个方法计算result的值并与输入的值进行比较
                {
                    MessageBox.Show("回答正确！");
                    listBox2.Items.Add(result + "=" + textBox2.Text + "  " + "√");//若答对直接后面打个对勾。
                    listBox1.Items.Remove(listBox1.SelectedItem);
                    right++;
                }

                else
                {
                    MessageBox.Show("答题错误！");
                    listBox2.Items.Add(result + "=" + textBox2.Text + "  " + "×");//若答错就在后面打个错号。
                    listBox1.Items.Remove(listBox1.SelectedItem);
                }
                label1.Text = "正确率：" + Convert.ToString(right * 1.0 / Count * 100).PadRight(5, ' ').Substring(0, 5) + "%";
                textBox1.Clear();
                textBox2.Clear();
            }
        }
    }
}

运行测试：

出题界面：

答题界面：

提示结束：

保存：