最近重新翻起以前学的数据结构,原来是用C写的,今天用C#重新回温一下,加深一点印象.
目前还不支持单目操作符,只支持双目的,以后改进吧.:)
using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;
namespace Expression1{ /// <summary> /// Form1 的摘要说明。 /// </summary> public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.Label label1; private System.Windows.Forms.Label label2; private System.Windows.Forms.TextBox txtInfix; private System.Windows.Forms.TextBox txtPostfix; private System.Windows.Forms.Button btnPostfix; private System.Windows.Forms.Button btnCalc; private System.Windows.Forms.TextBox txtCalc; /// <summary> /// 必需的设计器变量。 /// </summary> private System.ComponentModel.Container components = null;
public Form1() { // // Windows 窗体设计器支持所必需的 // InitializeComponent();
// // TODO: 在 InitializeComponent 调用后添加任何构造函数代码 // }
/// <summary> /// 清理所有正在使用的资源。 /// </summary> protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); }
#region Windows 窗体设计器生成的代码 /// <summary> /// 设计器支持所需的方法 - 不要使用代码编辑器修改 /// 此方法的内容。 /// </summary> private void InitializeComponent() { this.txtInfix = new System.Windows.Forms.TextBox(); this.txtPostfix = new System.Windows.Forms.TextBox(); this.btnPostfix = new System.Windows.Forms.Button(); this.label1 = new System.Windows.Forms.Label(); this.label2 = new System.Windows.Forms.Label(); this.btnCalc = new System.Windows.Forms.Button(); this.txtCalc = new System.Windows.Forms.TextBox(); this.SuspendLayout(); // // txtInfix // this.txtInfix.Location = new System.Drawing.Point(88, 24); this.txtInfix.Name = "txtInfix"; this.txtInfix.Size = new System.Drawing.Size(176, 21); this.txtInfix.TabIndex = 0; this.txtInfix.Text = ""; // // txtPostfix // this.txtPostfix.Location = new System.Drawing.Point(88, 88); this.txtPostfix.Name = "txtPostfix"; this.txtPostfix.Size = new System.Drawing.Size(176, 21); this.txtPostfix.TabIndex = 1; this.txtPostfix.Text = ""; // // btnPostfix // this.btnPostfix.FlatStyle = System.Windows.Forms.FlatStyle.System; this.btnPostfix.Location = new System.Drawing.Point(120, 56); this.btnPostfix.Name = "btnPostfix"; this.btnPostfix.TabIndex = 2; this.btnPostfix.Text = "转化"; this.btnPostfix.Click += new System.EventHandler(this.btnPostfix_Click); // // label1 // this.label1.Location = new System.Drawing.Point(8, 24); this.label1.Name = "label1"; this.label1.Size = new System.Drawing.Size(72, 23); this.label1.TabIndex = 3; this.label1.Text = "中缀表达式"; this.label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; // // label2 // this.label2.Location = new System.Drawing.Point(8, 88); this.label2.Name = "label2"; this.label2.Size = new System.Drawing.Size(72, 23); this.label2.TabIndex = 4; this.label2.Text = "后缀表达式"; this.label2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; // // btnCalc // this.btnCalc.FlatStyle = System.Windows.Forms.FlatStyle.System; this.btnCalc.Location = new System.Drawing.Point(24, 136); this.btnCalc.Name = "btnCalc"; this.btnCalc.TabIndex = 5; this.btnCalc.Text = "计算结果"; this.btnCalc.Click += new System.EventHandler(this.btnCalc_Click); // // txtCalc // this.txtCalc.Location = new System.Drawing.Point(120, 136); this.txtCalc.Name = "txtCalc"; this.txtCalc.Size = new System.Drawing.Size(144, 21); this.txtCalc.TabIndex = 6; this.txtCalc.Text = ""; // // Form1 // this.AutoScaleBaseSize = new System.Drawing.Size(6, 14); this.ClientSize = new System.Drawing.Size(292, 182); this.Controls.Add(this.txtCalc); this.Controls.Add(this.btnCalc); this.Controls.Add(this.label2); this.Controls.Add(this.label1); this.Controls.Add(this.btnPostfix); this.Controls.Add(this.txtPostfix); this.Controls.Add(this.txtInfix); this.MaximizeBox = false; this.Name = "Form1"; this.Text = "表达式计算"; this.ResumeLayout(false);
} #endregion
/// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.DoEvents(); Application.Run(new Form1()); }
private void btnPostfix_Click(object sender, System.EventArgs e) { try { Calculator calc = new Calculator(this.txtInfix.Text.Replace(" ","")); this.txtPostfix.Text = calc.PostFix(); } catch(Expressception ex) { MessageBox.Show(ex.Message); } }
private void btnCalc_Click(object sender, System.EventArgs e) { try { Calculator calc = new Calculator(this.txtInfix.Text.Replace(" ","")); this.txtCalc.Text = calc.Run().ToString(); } catch(Expressception ex) { MessageBox.Show(ex.Message); } } }
public class Calculator { private string _expression; private Stack s;
public Calculator(string expression) { this._expression = expression; s = new Stack(); }
public double Run() { string expression=PostFix(); string[] aryString = expression.Split('|');
foreach(string str in aryString) { if(IsNumber(str)) { double d = Convert.ToDouble(str.ToString()); AddOperands(d); } else { DoOperator(str); }
} return (double)s.Pop(); }
private bool IsNumber(string str) { if(str.Length>1) { return true; } else { return Char.IsDigit(str[0]); } }
private void AddOperands(double val) { s.Push(val); }
private bool Get2Operands(out double left,out double right) { try { right = (double)s.Pop(); left = (double)s.Pop(); } catch(InvalidOperationException) { right = 0; left = 0; return false; } return true; }
private void DoOperator(string op) { double left,right; bool result = Get2Operands(out left,out right); if(result) switch(op) { case "+": s.Push(left+right); break; case "-": s.Push(left-right); break; case "*": s.Push(left*right); break; case "/": if(right == 0.0) { s.Clear(); //Divide by 0! throw new Expressception("除数不能为零"); } else s.Push(left/right); break; case "^": s.Push(Math.Pow(left,right)); break; } else s.Clear(); }
public string PostFix() { string str = this._expression+"#"; char tempc; char[] chars = str.ToCharArray(); Stack ts = new Stack(); ts.Push('#'); string str1=""; string tmpStr=""; bool isNum = false; foreach(char c in chars) { if(Char.IsDigit(c)||c=='.') { tmpStr += c.ToString(); isNum = true; } else { if(isNum) { str1 += tmpStr+"|"; tmpStr = ""; } isNum=false; if(c == ')') { for(tempc = Convert.ToChar(ts.Pop());tempc!='(';tempc = Convert.ToChar(ts.Pop())) str1+=tempc.ToString()+"|"; } else { for(tempc = Convert.ToChar(ts.Pop());Isp(tempc)>Icp(c);tempc = Convert.ToChar(ts.Pop())) str1+=tempc.ToString()+"|"; ts.Push(tempc); ts.Push(c); } } } return str1.Substring(0,str1.Length-1); }
private int Isp(char c) { int k; switch(c) { case '#': k=0; break; case '(': k=1; break; case '^': k=7; break; case '*': case '/': case '%': k=5; break; case '+': case '-': k=3; break; case ')': k=8; break; default: //Unknown operator! throw new Expressception("不知道的操作符!"); } return k; }
private int Icp(char c) { int k; switch(c) { case '#': k=0; break; case '(': k=8; break; case '^': k=6; break; case '*': case '/': case '%': k=4; break; case '+': case '-': k=2; break; case ')': k=1; break; default: //Unknown operator! throw new Expressception("不知道的操作符!"); } return k; }
}
public class Expressception : Exception { public Expressception(string msg) : base(msg) { } }
