Evaluating string 3 4 2 yield int 18

Question

Is there a function the  NET framework that can evaluate a numeric expression contained in a string and return the result  F e    string mystring    3  2 4    int result   EvaluateExpression mystring   Console Writeln result      Outputs 18   Is there a standard framework function that you can replace my EvaluateExpression method with

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There is not  You will need to use some external library  or write your own parser  If you  have the time to do so  I suggest to write your own parser as it is a quite interesting project  Otherwise you will need to use something like bcParser

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You could fairly easily run this through the CSharpCodeProvider with suitable fluff wrapping it  a type and a method  basically   Likewise you could go through VB etc - or JavaScript  as another answer has suggested  I don t know of anything else built into the framework at this point   I d expect that  NET 4 0 with its support for dynamic languages may well have better capabilities on this front

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You could look at  XpathNavigator Evaluate  I have used this to process mathematical expressions for my GridView and it works fine for me   Here is the code I used for my program   public static double Evaluate string expression        return  double new System Xml XPath XPathDocument      new StringReader   lt r  gt     CreateNavigator   Evaluate      string Format  number  0     new     System Text RegularExpressions Regex        -            Replace expression      1          Replace        div         Replace        mod

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Many thanks to Ramesh   I used a version of his simple code to pull a string out a database and use it to do boolean operations in my code   x is a number like 1500 or 2100 or whatever   function would be a stored evaluation like x   1400 and x  lt  1600  function   relation 0  Replace  and    amp  amp    Replace  x  x    DataTable f dt   new DataTable    var f var   f dt Compute function       if  bool Parse f var ToString      do stuff

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Short answer  I don t think so  C   Net is compiled  to bytecode  and can t evaluate strings at runtime  as far as I know  JScript  Net can  however  but I would still advise you to code a parser and stack-based evaluator yourself

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Try this   static double Evaluate string expression      var loDataTable   new DataTable      var loDataColumn   new DataColumn  Eval   typeof  double   expression     loDataTable Columns Add loDataColumn     loDataTable Rows Add 0     return  double   loDataTable Rows 0   Eval

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If you want to evaluate a string expression use the below code snippet   using System Data   DataTable dt   new DataTable    var v   dt Compute  3    2 4

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This is a simple Expression Evaluator using Stacks  public class MathEvaluator       public static void Run                 Eval   1 2             Eval  5 4 2            Eval    3 5 -6                public static void Eval string input                var ans   Evaluate input           Console WriteLine input           ans              public static double Evaluate String input                String expr         input                Stack lt String gt  ops   new Stack lt String gt             Stack lt Double gt  vals   new Stack lt Double gt              for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1               if  s Equals                     else if  s Equals       ops Push s               else if  s Equals  -    ops Push s               else if  s Equals       ops Push s               else if  s Equals       ops Push s               else if  s Equals  sqrt    ops Push s               else if  s Equals                                     int count   ops Count                  while  count  gt  0                                        String op   ops Pop                        double v   vals Pop                        if  op Equals       v   vals Pop     v                      else if  op Equals  -    v   vals Pop   - v                      else if  op Equals       v   vals Pop   v                      else if  op Equals       v   vals Pop   v                      else if  op Equals  sqrt    v   Math Sqrt v                       vals Push v                        count--                                              else vals Push Double Parse s                      return vals Pop

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I recently needed to do this for a project and I ended up using IronPython to do it  You can declare an instance of the engine  and then pass any valid python expression and get the result  If you re just doing simple math expressions  then it would suffice  My code ended up looking similar to   IronPython Hosting PythonEngine pythonEngine   new IronPython Hosting PythonEngine    string expression    3  2 4    double result   pythonEngine EvaluateAs lt double gt  expression     You d probably not want to create the engine for each expression  You also need a reference to IronPython dll

User · Answer

There is not  You will need to use some external library  or write your own parser  If you  have the time to do so  I suggest to write your own parser as it is a quite interesting project  Otherwise you will need to use something like bcParser

User · Answer

If you want to evaluate a string expression use the below code snippet   using System Data   DataTable dt   new DataTable    var v   dt Compute  3    2 4

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Using the compiler to do implies memory leaks as the generated assemblies are loaded and never released  It s also less performant than using a real expression interpreter  For this purpose you can use Ncalc which is an open-source framework with this solely intent  You can also define your own variables and custom functions if the ones already included aren t enough   Example   Expression e   new Expression  2   3   5    Debug Assert 17    e Evaluate

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EDIT  Realised i should really bring the addition and subtraction out seperately aswell to make it a little bit more BODMAS compliant   Big thanks to Rajesh Jinaga for his Stack based approach  I found it really useful for my needs  The following code is a slight modification of Rajesh s method  which processes divisions first  then multiplications  then finishes up with addition and subtraction  It will also allow the use of booleans in the expressions  where true is treated as 1 and false 0  allowing the use of boolean logic in expressions   public static double Evaluate string expr                expr   expr ToLower            expr   expr Replace                   expr   expr Replace  true    1            expr   expr Replace  false    0             Stack lt String gt  stack   new Stack lt String gt              string value               for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1                  pick up any doublelogical operators first              if  i  lt  expr Length - 1                                String op   expr Substring i  2                   if  op      lt       op      gt       op                                                stack Push value                       value                           stack Push op                       i                        continue                                               char chr   s ToCharArray   0                if   char IsDigit chr   amp  amp  chr         amp  amp  value                                      stack Push value                   value                                 if  s Equals                                     string innerExp                       i      Fetch Next Character                 int bracketCount   0                  for    i  lt  expr Length  i                                          s   expr Substring i  1                        if  s Equals       bracketCount                         if  s Equals                                                     if  bracketCount    0  break                          bracketCount--                                            innerExp    s                                    stack Push Evaluate innerExp  ToString                               else if  s Equals                              s Equals  -                           s Equals                              s Equals                              s Equals   lt                            s Equals   gt                                   stack Push s                             else if  char IsDigit chr     chr                                       value    s                   if  value Split      Length  gt  2                      throw new Exception  Invalid decimal                      if  i     expr Length - 1                       stack Push value                              else                               throw new Exception  Invalid character                                      double result   0          List lt String gt  list   stack ToList lt String gt             for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                   for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  for  int i   list Count - 2  i  gt   0  i--                        if  list i      -                                 list i     Convert ToDouble list i - 1   - Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  stack Clear            for  int i   0  i  lt  list Count  i                          stack Push list i                      while  stack Count  gt   3                        double right   Convert ToDouble stack Pop                 string op   stack Pop                double left   Convert ToDouble stack Pop                  if  op      lt    result    left  lt  right    1   0              else if  op      gt    result    left  gt  right    1   0              else if  op      lt     result    left  lt   right    1   0              else if  op      gt     result    left  gt   right    1   0              else if  op          result    left    right    1   0               stack Push result ToString                       return Convert ToDouble stack Pop             I know there is likely to be a cleaner way of doing it  thought id just share the first look at it in case anyone finds it usefull

User · Answer

You could fairly easily run this through the CSharpCodeProvider with suitable fluff wrapping it  a type and a method  basically   Likewise you could go through VB etc - or JavaScript  as another answer has suggested  I don t know of anything else built into the framework at this point   I d expect that  NET 4 0 with its support for dynamic languages may well have better capabilities on this front

User · Answer

You could look at  XpathNavigator Evaluate  I have used this to process mathematical expressions for my GridView and it works fine for me   Here is the code I used for my program   public static double Evaluate string expression        return  double new System Xml XPath XPathDocument      new StringReader   lt r  gt     CreateNavigator   Evaluate      string Format  number  0     new     System Text RegularExpressions Regex        -            Replace expression      1          Replace        div         Replace        mod

User · Answer

Short answer  I don t think so  C   Net is compiled  to bytecode  and can t evaluate strings at runtime  as far as I know  JScript  Net can  however  but I would still advise you to code a parser and stack-based evaluator yourself

User · Answer

You could fairly easily run this through the CSharpCodeProvider with suitable fluff wrapping it  a type and a method  basically   Likewise you could go through VB etc - or JavaScript  as another answer has suggested  I don t know of anything else built into the framework at this point   I d expect that  NET 4 0 with its support for dynamic languages may well have better capabilities on this front

User · Answer

There is not  You will need to use some external library  or write your own parser  If you  have the time to do so  I suggest to write your own parser as it is a quite interesting project  Otherwise you will need to use something like bcParser

User · Answer

I recently needed to do this for a project and I ended up using IronPython to do it  You can declare an instance of the engine  and then pass any valid python expression and get the result  If you re just doing simple math expressions  then it would suffice  My code ended up looking similar to   IronPython Hosting PythonEngine pythonEngine   new IronPython Hosting PythonEngine    string expression    3  2 4    double result   pythonEngine EvaluateAs lt double gt  expression     You d probably not want to create the engine for each expression  You also need a reference to IronPython dll

User · Answer

I recently needed to do this for a project and I ended up using IronPython to do it  You can declare an instance of the engine  and then pass any valid python expression and get the result  If you re just doing simple math expressions  then it would suffice  My code ended up looking similar to   IronPython Hosting PythonEngine pythonEngine   new IronPython Hosting PythonEngine    string expression    3  2 4    double result   pythonEngine EvaluateAs lt double gt  expression     You d probably not want to create the engine for each expression  You also need a reference to IronPython dll

User · Answer

Using the compiler to do implies memory leaks as the generated assemblies are loaded and never released  It s also less performant than using a real expression interpreter  For this purpose you can use Ncalc which is an open-source framework with this solely intent  You can also define your own variables and custom functions if the ones already included aren t enough   Example   Expression e   new Expression  2   3   5    Debug Assert 17    e Evaluate

User · Answer

static double Evaluate string expression       var loDataTable   new DataTable       var loDataColumn   new DataColumn  Eval   typeof  double   expression      loDataTable Columns Add loDataColumn      loDataTable Rows Add 0      return  double   loDataTable Rows 0   Eval           Explanation of how it works   First  we make a table in the part var loDataTable   new DataTable     just like in a Data Base Engine  MS SQL for example    Then  a column  with some specific parameters  var loDataColumn   new DataColumn  Eval   typeof  double   expression      The  Eval  parameter is the name of the column  ColumnName attribute    typeof  double  is the type of data to be stored in the column  which is equal to put System Type GetType  System Double    instead   expression is the string that the Evaluate method receives  and is stored in the attribute Expression of the column  This attribute is for a really specific purpose  obvious   which is that every row that s put on the column will be fullfilled with the  Expression   and it accepts practically wathever can be put in a SQL Query  Refer to http   msdn microsoft com en-us library system data datacolumn expression v vs 100  aspx to know what can be put in the Expression attribute  and how it s evaluated   Then  loDataTable Columns Add loDataColumn   adds the column loDataColumn to the loDataTable table   Then  a row is added to the table with a personalized column with a Expression attribute  done via loDataTable Rows Add 0    When we add this row  the cell of the column  Eval  of the table loDataTable is fullfilled automatically with its  Expression  attribute  and  if it has operators and SQL Queries  etc  it s evaluated and then stored to the cell  so  here happens the  magic   the string with operators is evaluated and stored to a cell     Finally  just return the value stored to the cell of the column  Eval  in row 0  it s an index  starts counting from zero   and making a conversion to a double with return  double   loDataTable Rows 0   Eval       And that s all    job done   And here a code eaiser to understand  which does the same    It s not inside a method  and it s explained too   DataTable MyTable   new DataTable    DataColumn MyColumn   new DataColumn    MyColumn ColumnName    MyColumn   MyColumn Expression    5 5 5  MyColumn DataType   typeof double   MyTable Columns Add MyColumn   DataRow MyRow   MyTable NewRow    MyTable Rows Add MyRow   return  double  MyTable Rows 0   MyColumn       First  create the table with DataTable MyTable   new DataTable     Then  a column with DataColumn MyColumn   new DataColumn     Next  we put a name to the column  This so we can search into it s contents when it s stored to the table  Done via MyColumn ColumnName    MyColumn    Then  the Expression  here we can put a variable of type string  in this case there s a predefined string  5 5 5   which result is 6   The type of data to be stored to the column MyColumn DataType   typeof double    Add the column to the table    MyTable Columns Add MyColumn    Make a row to be inserted to the table  which copies the table structure DataRow MyRow   MyTable NewRow     Add the row to the table with MyTable Rows Add MyRow    And return the value of the cell in row 0 of the column MyColumn of the table MyTable with return  double  MyTable Rows 0   MyColumn      Lesson done

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This is right to left execution  so need to use proper parathesis to execute expression         2  100 5  10   32         2 5 10  5  2 5   5         2 5 10  5 2 5   1 6666     public static double Evaluate String expr                 Stack lt String gt  stack   new Stack lt String gt              string value               for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1               char chr   s ToCharArray   0                if   char IsDigit chr   amp  amp  chr         amp  amp  value                                      stack Push value                   value                                  if  s Equals                          string innerExp                       i      Fetch Next Character                 int bracketCount 0                  for    i  lt  expr Length  i                                          s   expr Substring i  1                        if  s Equals                               bracketCount                         if  s Equals                               if  bracketCount    0                              break                          else                             bracketCount--                        innerExp    s                                     stack Push Evaluate innerExp  ToString                                else if  s Equals       stack Push s               else if  s Equals  -    stack Push s               else if  s Equals       stack Push s               else if  s Equals       stack Push s               else if  s Equals  sqrt    stack Push s               else if  s Equals                                               else if  char IsDigit chr     chr                                       value    s                   if  value Split      Length  gt  2                      throw new Exception  Invalid decimal                      if  i     expr Length - 1                       stack Push value                              else                 throw new Exception  Invalid character                          double result   0          while  stack Count  gt   3                         double right   Convert ToDouble stack Pop                 string op   stack Pop                double left   Convert ToDouble stack Pop                  if  op         result   left   right              else if  op         result   left   right              else if  op     -   result   left - right              else if  op         result   left   right              else if  op         result   left   right               stack Push result ToString                         return Convert ToDouble stack Pop

User · Answer

Short answer  I don t think so  C   Net is compiled  to bytecode  and can t evaluate strings at runtime  as far as I know  JScript  Net can  however  but I would still advise you to code a parser and stack-based evaluator yourself

User · Answer

static double Evaluate string expression       var loDataTable   new DataTable       var loDataColumn   new DataColumn  Eval   typeof  double   expression      loDataTable Columns Add loDataColumn      loDataTable Rows Add 0      return  double   loDataTable Rows 0   Eval           Explanation of how it works   First  we make a table in the part var loDataTable   new DataTable     just like in a Data Base Engine  MS SQL for example    Then  a column  with some specific parameters  var loDataColumn   new DataColumn  Eval   typeof  double   expression      The  Eval  parameter is the name of the column  ColumnName attribute    typeof  double  is the type of data to be stored in the column  which is equal to put System Type GetType  System Double    instead   expression is the string that the Evaluate method receives  and is stored in the attribute Expression of the column  This attribute is for a really specific purpose  obvious   which is that every row that s put on the column will be fullfilled with the  Expression   and it accepts practically wathever can be put in a SQL Query  Refer to http   msdn microsoft com en-us library system data datacolumn expression v vs 100  aspx to know what can be put in the Expression attribute  and how it s evaluated   Then  loDataTable Columns Add loDataColumn   adds the column loDataColumn to the loDataTable table   Then  a row is added to the table with a personalized column with a Expression attribute  done via loDataTable Rows Add 0    When we add this row  the cell of the column  Eval  of the table loDataTable is fullfilled automatically with its  Expression  attribute  and  if it has operators and SQL Queries  etc  it s evaluated and then stored to the cell  so  here happens the  magic   the string with operators is evaluated and stored to a cell     Finally  just return the value stored to the cell of the column  Eval  in row 0  it s an index  starts counting from zero   and making a conversion to a double with return  double   loDataTable Rows 0   Eval       And that s all    job done   And here a code eaiser to understand  which does the same    It s not inside a method  and it s explained too   DataTable MyTable   new DataTable    DataColumn MyColumn   new DataColumn    MyColumn ColumnName    MyColumn   MyColumn Expression    5 5 5  MyColumn DataType   typeof double   MyTable Columns Add MyColumn   DataRow MyRow   MyTable NewRow    MyTable Rows Add MyRow   return  double  MyTable Rows 0   MyColumn       First  create the table with DataTable MyTable   new DataTable     Then  a column with DataColumn MyColumn   new DataColumn     Next  we put a name to the column  This so we can search into it s contents when it s stored to the table  Done via MyColumn ColumnName    MyColumn    Then  the Expression  here we can put a variable of type string  in this case there s a predefined string  5 5 5   which result is 6   The type of data to be stored to the column MyColumn DataType   typeof double    Add the column to the table    MyTable Columns Add MyColumn    Make a row to be inserted to the table  which copies the table structure DataRow MyRow   MyTable NewRow     Add the row to the table with MyTable Rows Add MyRow    And return the value of the cell in row 0 of the column MyColumn of the table MyTable with return  double  MyTable Rows 0   MyColumn      Lesson done

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You could fairly easily run this through the CSharpCodeProvider with suitable fluff wrapping it  a type and a method  basically   Likewise you could go through VB etc - or JavaScript  as another answer has suggested  I don t know of anything else built into the framework at this point   I d expect that  NET 4 0 with its support for dynamic languages may well have better capabilities on this front

User · Answer

This is a simple Expression Evaluator using Stacks  public class MathEvaluator       public static void Run                 Eval   1 2             Eval  5 4 2            Eval    3 5 -6                public static void Eval string input                var ans   Evaluate input           Console WriteLine input           ans              public static double Evaluate String input                String expr         input                Stack lt String gt  ops   new Stack lt String gt             Stack lt Double gt  vals   new Stack lt Double gt              for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1               if  s Equals                     else if  s Equals       ops Push s               else if  s Equals  -    ops Push s               else if  s Equals       ops Push s               else if  s Equals       ops Push s               else if  s Equals  sqrt    ops Push s               else if  s Equals                                     int count   ops Count                  while  count  gt  0                                        String op   ops Pop                        double v   vals Pop                        if  op Equals       v   vals Pop     v                      else if  op Equals  -    v   vals Pop   - v                      else if  op Equals       v   vals Pop   v                      else if  op Equals       v   vals Pop   v                      else if  op Equals  sqrt    v   Math Sqrt v                       vals Push v                        count--                                              else vals Push Double Parse s                      return vals Pop

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Many thanks to Ramesh   I used a version of his simple code to pull a string out a database and use it to do boolean operations in my code   x is a number like 1500 or 2100 or whatever   function would be a stored evaluation like x   1400 and x  lt  1600  function   relation 0  Replace  and    amp  amp    Replace  x  x    DataTable f dt   new DataTable    var f var   f dt Compute function       if  bool Parse f var ToString      do stuff

User · Answer

Short answer  I don t think so  C   Net is compiled  to bytecode  and can t evaluate strings at runtime  as far as I know  JScript  Net can  however  but I would still advise you to code a parser and stack-based evaluator yourself

User · Answer

Try this   static double Evaluate string expression      var loDataTable   new DataTable      var loDataColumn   new DataColumn  Eval   typeof  double   expression     loDataTable Columns Add loDataColumn     loDataTable Rows Add 0     return  double   loDataTable Rows 0   Eval

User · Answer

There is not  You will need to use some external library  or write your own parser  If you  have the time to do so  I suggest to write your own parser as it is a quite interesting project  Otherwise you will need to use something like bcParser

User · Answer

I recently needed to do this for a project and I ended up using IronPython to do it  You can declare an instance of the engine  and then pass any valid python expression and get the result  If you re just doing simple math expressions  then it would suffice  My code ended up looking similar to   IronPython Hosting PythonEngine pythonEngine   new IronPython Hosting PythonEngine    string expression    3  2 4    double result   pythonEngine EvaluateAs lt double gt  expression     You d probably not want to create the engine for each expression  You also need a reference to IronPython dll

User · Answer

This is right to left execution  so need to use proper parathesis to execute expression         2  100 5  10   32         2 5 10  5  2 5   5         2 5 10  5 2 5   1 6666     public static double Evaluate String expr                 Stack lt String gt  stack   new Stack lt String gt              string value               for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1               char chr   s ToCharArray   0                if   char IsDigit chr   amp  amp  chr         amp  amp  value                                      stack Push value                   value                                  if  s Equals                          string innerExp                       i      Fetch Next Character                 int bracketCount 0                  for    i  lt  expr Length  i                                          s   expr Substring i  1                        if  s Equals                               bracketCount                         if  s Equals                               if  bracketCount    0                              break                          else                             bracketCount--                        innerExp    s                                     stack Push Evaluate innerExp  ToString                                else if  s Equals       stack Push s               else if  s Equals  -    stack Push s               else if  s Equals       stack Push s               else if  s Equals       stack Push s               else if  s Equals  sqrt    stack Push s               else if  s Equals                                               else if  char IsDigit chr     chr                                       value    s                   if  value Split      Length  gt  2                      throw new Exception  Invalid decimal                      if  i     expr Length - 1                       stack Push value                              else                 throw new Exception  Invalid character                          double result   0          while  stack Count  gt   3                         double right   Convert ToDouble stack Pop                 string op   stack Pop                double left   Convert ToDouble stack Pop                  if  op         result   left   right              else if  op         result   left   right              else if  op     -   result   left - right              else if  op         result   left   right              else if  op         result   left   right               stack Push result ToString                         return Convert ToDouble stack Pop

User · Answer

EDIT  Realised i should really bring the addition and subtraction out seperately aswell to make it a little bit more BODMAS compliant   Big thanks to Rajesh Jinaga for his Stack based approach  I found it really useful for my needs  The following code is a slight modification of Rajesh s method  which processes divisions first  then multiplications  then finishes up with addition and subtraction  It will also allow the use of booleans in the expressions  where true is treated as 1 and false 0  allowing the use of boolean logic in expressions   public static double Evaluate string expr                expr   expr ToLower            expr   expr Replace                   expr   expr Replace  true    1            expr   expr Replace  false    0             Stack lt String gt  stack   new Stack lt String gt              string value               for  int i   0  i  lt  expr Length  i                          String s   expr Substring i  1                  pick up any doublelogical operators first              if  i  lt  expr Length - 1                                String op   expr Substring i  2                   if  op      lt       op      gt       op                                                stack Push value                       value                           stack Push op                       i                        continue                                               char chr   s ToCharArray   0                if   char IsDigit chr   amp  amp  chr         amp  amp  value                                      stack Push value                   value                                 if  s Equals                                     string innerExp                       i      Fetch Next Character                 int bracketCount   0                  for    i  lt  expr Length  i                                          s   expr Substring i  1                        if  s Equals       bracketCount                         if  s Equals                                                     if  bracketCount    0  break                          bracketCount--                                            innerExp    s                                    stack Push Evaluate innerExp  ToString                               else if  s Equals                              s Equals  -                           s Equals                              s Equals                              s Equals   lt                            s Equals   gt                                   stack Push s                             else if  char IsDigit chr     chr                                       value    s                   if  value Split      Length  gt  2                      throw new Exception  Invalid decimal                      if  i     expr Length - 1                       stack Push value                              else                               throw new Exception  Invalid character                                      double result   0          List lt String gt  list   stack ToList lt String gt             for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                   for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  for  int i   list Count - 2  i  gt   0  i--                        if  list i                                        list i     Convert ToDouble list i - 1     Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  for  int i   list Count - 2  i  gt   0  i--                        if  list i      -                                 list i     Convert ToDouble list i - 1   - Convert ToDouble list i   1    ToString                    list RemoveAt i   1                   list RemoveAt i - 1                   i -  2                                  stack Clear            for  int i   0  i  lt  list Count  i                          stack Push list i                      while  stack Count  gt   3                        double right   Convert ToDouble stack Pop                 string op   stack Pop                double left   Convert ToDouble stack Pop                  if  op      lt    result    left  lt  right    1   0              else if  op      gt    result    left  gt  right    1   0              else if  op      lt     result    left  lt   right    1   0              else if  op      gt     result    left  gt   right    1   0              else if  op          result    left    right    1   0               stack Push result ToString                       return Convert ToDouble stack Pop             I know there is likely to be a cleaner way of doing it  thought id just share the first look at it in case anyone finds it usefull

[c#] Evaluating string "3*(4+2)" yield int 18

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