public static Double GetResultFromStr(string source) { string str = InsertBlank(source); string rpnExperssion = ConvertToRPN(str); return GetResult(rpnExperssion); } private static double GetValue(double left, double right, char _operator) { switch (_operator) { case '+': return left+right; case '-': return left-right; case '*': return left*right; case '/': return left/right; } return 0; } private static double GetResult(string source) { try { source = source.Trim(); Stack<string> stack = new Stack<string>(); var list = source.Split(' '); for (int i = 0; i < list.Length; i++) { string current = list[i]; //bool b = Regex.IsMatch(strNum, "^[0-9]*{1}quot;); if (GetNum(current)) { stack.Push(current); } else if (OperatorLevel.ContainsKey(current)) { double right = double.Parse(stack.Pop()); double left = double.Parse(stack.Pop()); stack.Push(GetValue(left, right, current[0]).ToString()); } } string aaa = stack.Pop().ToString(); return double.Parse(aaa); } catch (Exception e) { } return 0; } private static string ConvertToRPN(string source) { try { StringBuilder result = new StringBuilder(); Stack<string> stack = new Stack<string>(); string[] list = source.Split(' '); for (int i = 0; i < list.Length; i++) { string current = list[i]; //if (Regex.IsMatch(current, "^([0-9]{1,}){1}quot;")) if (GetNum(current)) { result.Append(current + " "); } else if (OperatorLevel.ContainsKey(current)) { if (stack.Count > 0) { var prev = stack.Peek(); if (prev == "(") { stack.Push(current); continue; } if (current == "(") { stack.Push(current); continue; } if (current == ")") { while (stack.Count > 0 && stack.Peek() != "(") { result.Append(stack.Pop() + " "); } //Pop the "(" stack.Pop(); continue; } if (OperatorLevel[current] < OperatorLevel[prev]) { while (stack.Count > 0) { var top = stack.Pop(); if (top != "(" && top != ")") { result.Append(top + " "); } else { break; } } stack.Push(current); } else { stack.Push(current); } } else { stack.Push(current); } } } if (stack.Count > 0) { while (stack.Count > 0) { var top = stack.Pop(); if (top != "(" && top != ")") { result.Append(top + " "); } } } return result.ToString().Trim(); } catch(Exception e) { } return ""; } private static string InsertBlank(string source) { StringBuilder sb = new StringBuilder(); var list = source.ToCharArray(); foreach (var temp in list) { if (OperatorLevel.ContainsKey(temp.ToString())) { sb.Append(" "); sb.Append(temp.ToString()); sb.Append(" "); } else { sb.Append(temp); } } return sb.ToString(); } private static Dictionary<string, int> OperatorLevel { get { if(_operatorLevel==null) { _operatorLevel = new Dictionary<string, int>(); _operatorLevel.Add("+", 0); _operatorLevel.Add("-", 0); _operatorLevel.Add("(", 1); _operatorLevel.Add("*", 1); _operatorLevel.Add("/", 1); _operatorLevel.Add(")", 0); } return _operatorLevel; } } /// <summary> /// 验证是不是数字(包含整数和小数) /// </summary> /// <param name="str"></param> /// <returns></returns> private static bool GetNum(string str) { bool b = false; try { double.Parse(str); b = true; } catch (Exception e) { } return b; }