数学表示试如：“2+（3/5+log(10)+exp(30)） + (5 +4/(-6))”
模型：
数学公式分为几个元素，
操作数 如：2 操作符 如：+ - * / 表达式：如(5 +4/(-6)) 或者数学方法log(10)
其实整个公式是一个表达式：
调用方式：
string mathexpstr = "2+5*5/6*30";
CalculaterExpression cc = new CalculaterExpression();
decimal result = cc.Calculate(mathexpstr);
以下是代码：
1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Reflection;
5 using System.Text;
6 using System.Threading.Tasks;
7
8 namespace Calculate
9 {
10 /******************************************************
11 *
12 * Author: zgtian
13 * Data: 2016/04/08
14 *
15 * ***************************************************/
16
17
18
19 /// <summary>
20 /// 表达式中负数必须用()括起来。比如 -1+2 修改为(-1)+2 在比如3/-2 改为 3/(-2),
21 /// 只支持单参数数学函数 比如log(200),暂不支持多参函数 比如 Atan2(a1,a2),
22 /// 例外：默认ln＝log10(number) pow=pow(e,number) e=exp(1)
23 /// </summary>
24 public class CalculaterExpression
25 {
26 public decimal Calculate(string expressionString)
27 {
28 Expression exp = ConvertStringToExpressionObject(expressionString);
29 return Calculate(exp);
30 }
31
32 /// <summary>
33 /// 把字符串表达式转换成表达式类对象
34 /// </summary>
35 /// <param name="expressionString"></param>
36 /// <returns></returns>
37 private Expression ConvertStringToExpressionObject(string expressionString)
38 {
39 char[] chs = expressionString.ToCharArray();
40 string str = expressionString.Substring(0, 1);
41 int startIndex = 0;
42 CharType preType = CharType.Unknown;
43 Expression expression = new Expression();
44
45 for (int i = 0; i < chs.Length; i++)
46 {
47 CharType currentCharType = GetCharType(chs[i]);
48 if (currentCharType != preType)
49 {
50 if (preType == CharType.NUMBER)
51 {
52 str = expressionString.Substring(startIndex, i - startIndex);
53 Decimal number = 0;
54 decimal.TryParse(str, out number);
55 expression.Operands.Add(number);
56 startIndex = i;
57 preType = currentCharType;
58 }
59 else if (!(preType == CharType.CHAR && currentCharType == CharType.LeftBracket))
60 {
61 startIndex = i;
62 preType = currentCharType;
63 }
64 }
65
66 switch (currentCharType)
67 {
68 case CharType.CHAR:
69 {
70 if (preType != CharType.CHAR)
71 {
72 startIndex = i;
73 preType = currentCharType;
74 }
75 }
76 break;
77 case CharType.ADD:
78 {
79 expression.Operators.Add(CalcOperator.ADD);
80 }
81 break;
82 case CharType.SUBTRACT:
83 {
84 expression.Operators.Add(CalcOperator.SUBTRACT);
85 }
86 break;
87 case CharType.MULTIPLY:
88 {
89 expression.Operators.Add(CalcOperator.MULTIPLY);
90 }
91 break;
92 case CharType.DIVIDE:
93 {
94 expression.Operators.Add(CalcOperator.DIVIDE);
95 }
96 break;
97 case CharType.LeftBracket:
98 {
99 Expression childExpression = new Expression();
100 childExpression.parentExpression = expression;
101 expression.childExpression = childExpression;
102 expression = childExpression;
103 if (preType == CharType.CHAR)
104 {
105 str = expressionString.Substring(startIndex, i - startIndex).ToLower();
106 str = str.Substring(0, 1).ToUpper() + str.Substring(1);
107 expression.FunctionName = str;
108 startIndex = i;
109 preType = currentCharType;
110 }
111 }
112 break;
113 case CharType.RightBracket:
114 {
115 expression.parentExpression.Operands.Add(expression);
116 expression = expression.parentExpression;
117 }
118 break;
119 case CharType.NUMBER:
120 break;
121
122 }
123 if (i == chs.Length - 1)
124 {
125 if (currentCharType == CharType.NUMBER)
126 {
127 str = expressionString.Substring(startIndex);
128 Decimal number = 0;
129 decimal.TryParse(str, out number);
130 expression.Operands.Add(number);
131 }
132 }
133 }
134 return expression;
135 }
136
137 /// <summary>
138 /// 计算表达式对象
139 /// </summary>
140 /// <param name="exp"></param>
141 /// <returns></returns>
142 private decimal Calculate(Expression exp)
143 {
144 decimal result = 0;
145 //先计算所有的表达式
146 for (int i = 0; i < exp.Operands.Count; i++)
147 {
148 if (typeof(Expression).IsInstanceOfType(exp.Operands[i]))
149 {
150 exp.Operands[i] = Calculate((Expression)exp.Operands[i]);
151 }
152 }
153
154 //计算乘除
155 for (int i = 0; i < exp.Operators.Count; i++)
156 {
157 CalcOperator ope = exp.Operators[i];
158 if (ope == CalcOperator.MULTIPLY)
159 {
160 exp.Operands[i] = (decimal)exp.Operands[i] * (decimal)exp.Operands[i + 1];
161 exp.Operands.Remove(exp.Operands[i + 1]);
162 exp.Operators.Remove(exp.Operators[i]);
163 i--;
164 }
165 else if (ope == CalcOperator.DIVIDE)
166 {
167 exp.Operands[i] = (decimal)exp.Operands[i] / (decimal)exp.Operands[i + 1];
168 exp.Operands.Remove(exp.Operands[i + 1]);
169 exp.Operators.Remove(exp.Operators[i]);
170 i--;
171 }
172 }
173
174 //最后计算所有的加减法
175 for (int i = 0; i < exp.Operators.Count; i++)
176 {
177 //负数比如(-1),如果此时的操作符不为-减号则解析错误
178 if (exp.Operands.Count == 1)
179 {
180 exp.Operands[0] = 0 - (decimal)exp.Operands[0];
181 break;
182 }
183
184 CalcOperator ope = exp.Operators[i];
185 if (ope == CalcOperator.ADD)
186 {
187 exp.Operands[i] = (decimal)exp.Operands[i] + (decimal)exp.Operands[i + 1];
188 }
189 else if (ope == CalcOperator.SUBTRACT)
190 {
191 exp.Operands[i] = (decimal)exp.Operands[i] - (decimal)exp.Operands[i + 1];
192 }
193 else
194 {
195 throw new Exception("数学表达式解析错误，还有非加减的运算符:" + exp.Operands[i].ToString() + ope.ToString() + exp.Operands[i+1].ToString());
196 }
197 exp.Operands.Remove(exp.Operands[i + 1]);
198 exp.Operators.Remove(exp.Operators[i]);
199 i--;
200
201 }
202 result = (decimal)exp.Operands[0];
203 //如果表达式是数学方法，则调用数学方法
204 if (exp.Operators.Count == 0)
205 {
206 if (!string.IsNullOrEmpty(exp.FunctionName))
207 {
208 result = CalcMathFunction(exp.FunctionName, (decimal)exp.Operands[0]);
209 exp.FunctionName = null;
210 }
211 }
212 return result;
213 }
214
215 /// <summary>
216 /// 数学方法，可以枚举出来，不必反射。
217 /// </summary>
218 /// <param name="functionName"></param>
219 /// <param name="value"></param>
220 /// <returns></returns>
221 private decimal CalcMathFunction(string functionName, decimal value)
222 {
223 try
224 {
225 if (functionName.ToLower() == "pow")
226 {
227 //项目需求唯一的一个需要2个参数的数学方法且底数固定为e Exp(1)
228 return Convert.ToDecimal(Math.Pow(Math.Exp(1), (double)value));
229 }
230
231 if (functionName.ToLower() == "ln")
232 {
233 functionName = "Log10";
234 }
235 MethodInfo[] mathMethods = typeof(Math).GetMethods(BindingFlags.Static | BindingFlags.InvokeMethod | BindingFlags.Public);
236 MethodInfo actureMethod = null;
237 for (int i = 0; i < mathMethods.Length; i++)
238 {
239 //只找一个参数的方法
240 if (mathMethods[i].Name == functionName && mathMethods[i].GetParameters().Length==1)
241 {
242 actureMethod = mathMethods[i];
243 break;
244 }
245 }
246
247 Type parameterType = actureMethod.GetParameters()[0].ParameterType;
248 string parameterTypeName = parameterType.Name;
249 MethodInfo convertMethod = typeof(Convert).GetMethod("To" + parameterTypeName, new Type[] { typeof(decimal) });
250 var parameter = convertMethod.Invoke(null, new object[] { value });
251 var result = actureMethod.Invoke(null, new Object[] { parameter });
252 return Convert.ToDecimal(result);
253 }
254 catch(Exception ex)
255 {
256 throw new Exception("数学方法错误，方法名：" + functionName + "，参数:" + value + "," + ex.StackTrace);
257 }
258
259 }
260
261
262 private bool IsNumber(char c)
263 {
264 if ((c >= 48 && c <= 57) || c == 46)
265 return true;
266 else
267 return false;
268 }
269
270 private bool IsOperator(char c)
271 {
272 bool result = false;
273 switch (c)
274 {
275 case ‘+‘:
276 case ‘-‘:
277 case ‘*‘:
278 case ‘/‘:
279 result = true;
280 break;
281 default:
282 break;
283 }
284 return result;
285 }
286
287 private bool IsCharacter(char c)
288 {
289 if ((c >= 65 && c <= 90) || (c >= 97 && c <= 122))
290 {
291 return true;
292 }
293 return false;
294 }
295
296
297 private CharType GetCharType(char c)
298 {
299 switch (c)
300 {
301 case ‘+‘:
302 return CharType.ADD;
303 case ‘-‘:
304 return CharType.SUBTRACT;
305 case ‘*‘:
306 return CharType.MULTIPLY;
307 case ‘/‘:
308 return CharType.DIVIDE;
309 default:
310 break;
311 }
312 if (IsCharacter(c))
313 return CharType.CHAR;
314 else if (IsNumber(c))
315 return CharType.NUMBER;
316 else if (c == ‘(‘)
317 return CharType.LeftBracket;
318 else if (c == ‘)‘)
319 return CharType.RightBracket;
320 return CharType.Unknown;
321 }
322
323 private enum CharType
324 {
325 ADD,SUBTRACT,MULTIPLY,DIVIDE,NUMBER,CHAR,LeftBracket,RightBracket,Unknown
326 }
327
328
329 }
330
331 /// <summary>
332 /// 计算表达式 如()阔起来的、数学方法log(10)
333 /// </summary>
334 internal class Expression
335 {
336 private List<Object> operand = new List<object>();
337 private List<CalcOperator> operators = new List<CalcOperator>();
338 public Expression parentExpression = null;
339 public Expression childExpression = null;
340
341 /// <summary>
342 /// 只有当表达式为方法时才赋值
343 /// </summary>
344 public string FunctionName { get; set; }
345
346 public List<Object> Operands { get { return operand; } }
347 public List<CalcOperator> Operators { get { return operators; } }
348 }
349
350 /// <summary>
351 /// 操作符
352 /// </summary>
353 internal enum CalcOperator
354 {
355 ADD, SUBTRACT, MULTIPLY, DIVIDE
356 }
357
358
359 }
时间： 2024-10-15 10:59:14