Anyone know of good resourses on implementing a Reverse Polish Notation expression parser? Not only explains the rules for handing the queue and stack, but also includes relational and logical operators. Just about any high level language, or good psuedo-code examples are a big plus.
207092
There's a very explicit algorithm which explains\nhow to handle number, operators (including left\nor right precedence), functions, etc. on the \nWikipedia site for RPN (see reference #1).\n\nMostly, it's very straight-forward.  If it's an operand\n(ie. a number), then push it on the stack.  If it's an\noperator, then pop off as many operands are needed and\nevaluate.\n\nBut do look at the full algorithm for the details.\n\nOh yeah, for a full-blown implementation, see the source\ncode to the Unix "dc" (desk calculator) program.  The\nSolaris source is at reference #2.
661474
#ifndef BINARY_SEARCH_TREE_H_\n        #define BINARY_SEARCH_TREE_H_\n\n        #include "dsexceptions.h"\n        #include <iostream.h>       // For NULL\n\n          // Binary node and forward declaration because g++ does\n          // not understand nested classes.\n        template <class Comparable>\n        class BinarySearchTree;\n\n        template <class Comparable>\n        class BinaryNode\n        {\n            Comparable element;\n            BinaryNode *left;\n            BinaryNode *right;\n\n            BinaryNode( const Comparable & theElement, BinaryNode *lt, BinaryNode *rt )\n              : element( theElement ), left( lt ), right( rt ) { }\n            friend class BinarySearchTree<Comparable>;\n        };\n\n\n        // BinarySearchTree class\n        //\n        // CONSTRUCTION: with ITEM_NOT_FOUND object used to signal failed finds\n        //\n        // ******************PUBLIC OPERATIONS*********************\n        // void insert( x )       --> Insert x\n        // void remove( x )       --> Remove x\n        // Comparable find( x )   --> Return item that matches x\n        // Comparable findMin( )  --> Return smallest item\n        // Comparable findMax( )  --> Return largest item\n        // boolean isEmpty( )     --> Return true if empty; else false\n        // void makeEmpty( )      --> Remove all items\n        // void printTree( )      --> Print tree in sorted order\n\n        template <class Comparable>\n        class BinarySearchTree\n        {\n          public:\n            explicit BinarySearchTree( const Comparable & notFound );\n            BinarySearchTree( const BinarySearchTree & rhs );\n            ~BinarySearchTree( );\n\n            const Comparable & findMin( ) const;\n            const Comparable & findMax( ) const;\n            const Comparable & find( const Comparable & x ) const;\n            bool isEmpty( ) const;\n            void printTree( ) const;\n\n            void makeEmpty( );\n            void insert( const Comparable & x );\n            void remove( const Comparable & x );\n\n            const BinarySearchTree & operator=( const BinarySearchTree & rhs );\n\n          private:\n            BinaryNode<Comparable> *root;\n            const Comparable ITEM_NOT_FOUND;\n\n            const Comparable & elementAt( BinaryNode<Comparable> *t ) const;\n\n            void insert( const Comparable & x, BinaryNode<Comparable> * & t ) const;\n            void remove( const Comparable & x, BinaryNode<Comparable> * & t ) const;\n            BinaryNode<Comparable> * findMin( BinaryNode<Comparable> *t ) const;\n            BinaryNode<Comparable> * findMax( BinaryNode<Comparable> *t ) const;\n            BinaryNode<Comparable> * find( const Comparable & x, BinaryNode<Comparable> *t ) const;\n            void makeEmpty( BinaryNode<Comparable> * & t ) const;\n            void printTree( BinaryNode<Comparable> *t ) const;\n            BinaryNode<Comparable> * clone( BinaryNode<Comparable> *t ) const;\n        };\n\n        #include "BinarySearchTree.cpp"\n        #endif
217040
I can see by looking at it that it won't compile.\nYou don't have semicolons at the end of the lines.\n\nI you put in the semicolons and replace the comma in the for loop with the another semicolon, it will compile and run.\n\nHowever, I don't think that you will get what you expect.\n\nYou use x without initializing it. That means that x will take the value that is already in memeory at that address.\n\nNext you condition your while loop on (R!=R) which is always false, so the while loop never executes.\n\nWhat you will print out is the last value that was left in x which is a location on the stack. \nI'm running MS C++ in debug mode, so it fills in the bytes of x with the value CC so you can recognize it as uninitialized stack memory.\n\nLast, you compute S but never use it.
503288
javap -c \nprints out "diassembled" java code. Each line, that starts with a number, followed by a colon is an "instruction". Just count those lines.
119747
Copy this and paste it into your code:\n\nOriginal = "Hello"\nLower = LCase(Original)\nUpper = UCase(Original)\nReverse = ""\nFor i = 1 To Len(Original)\n   If Mid(Original, i, 1) < Mid(Lower, i, 1) Then\n      Reverse = Reverse + Mid(Lower, i, 1)\n   Else\n      Reverse = Reverse + Mid(Upper, i, 1)\n   End If\nNext
38918
import java.util.*;\npublic class HelloWorld {   \n   public static Stack stack=new Stack(); \npublic static void main(String[] args) {\n   try {\n   String s="this is java string reverse ";\n   reverseString(s);\n   System.out.println("the reversed string value is ");\n   for(int i=stack.size()-1;i>=0;i--){\n   System.out.print(stack.get(i));\n   }\n       } \n   catch (Exception e) {\n            e.printStackTrace();\n       }\n    }\n   public static void reverseString(String s) throws Exception{\n      StringTokenizer temp=new StringTokenizer(s);\n   if(temp.hasMoreTokens()){\n   String s1=temp.nextToken();\n   stack.push(s1+" ");  \n   reverseString(s.substring(s1.length()+1));\n   }\n   else{\n   return;\n   }     \n   }  \n   \n}
93613
The EMACS text editor has a decode buffer mode. It's a little fiddly to use, but it allows you to apply any simple substitution cipher.\n\nIt should be easy to write a simple decoder using JavaScript / HTML by manipulating ASCII code values.\n\nEither way gets more complex if you want to decode accents.
390300
Briefly, it is about the same kind of difference as between chinese and korean...\nBoth use letters, and are understood by computers. But the syntax, lexic and vocabularies are different.\nHelps?\n\nBTW, one being "oops", and the other one not is really bull... Create a struct in "C", shove some pointers to functions into it, and enjoy your very own "object".\nNow, create another struct, with the previous one as the first field - and you have just discovered inheritance. Cast a pointer to the second one into a pointer to the first - and that is your polymorphism.\n\nAnother myth is that C++ is a "superset of C" or that you can compile a C program with a C++ compiler, or that C is "C++ without classes". This is not true. They look somewhat similar to a human eye, but formally are totally different laguages.\nYou could, probably, come up with some fairly simple C program, that can be compiled with C++, just like some Spanish words (and even sentenses) are also valid in French, but in general that is not true.\nFunction pointers are not compatible with void*, or with each other. Integers are not compatible with pointers, and are not assumed by default, you can't skip a type declaration etc, etc.\n\nAnd finally, no, "C" is not faster than "C++" on any sane system.
85964
Actually, this is Perl code.  Perl has support for regular expressions built into the language.  There are tools out there (such as "The Regulator") which can take regular expression strings and break them down into english statements that make it easier to understand them.\n\nHowever, from this code, it looks like it is storing a several regular expression strings into a collection.  From first glance, it appear that the strings look for certain text, most specifically for questions that probably appear on Yahoo! Answers.  For example, it looks like "quick and easy 10 point" or "an easy ten points" may be a match.\n\nThis is probably a script used to search for a pattern of questions and provide stock answers in an attempt to automate "point gaming".  I would strongly recommend against using it, especially after posting details about it here.
160571
http://www.senselang.com/\nhttp://www.alfatyping.com/index_en.php?remlng=true\nhttp://www.powertyping.com/rain.shtml\nhttp://www.powertyping.com/
34132
I dont think such a DFA exists if the order of 0's and 1's is not preserved. \n\nIf 0's and 1's are unordered and can appear randomly like 011001100, than such a DFA is not possible.\n\nReason:\n\nBecause you are trying to generate a regular expression. And meanwhile trying to find out its validity through count and compare method, hence it cannot be done..\n\nThere is a rule of thumb..\n1. if an expression's items can be counted, and the validity of the expression can be stated with a single comparison, then it is a context free grammar.\n\n2, if you need more than one comparison, it is a context sensitive grammar.\n\n3. regular expressions cannot be validated through count and compare\n\nHence by the elimination method due to contradiction, your problem cannot be solved.\n\nRegards\nParvesh
311681
class publication\n{\n   private :\n      char title[20];\n      float price;\n   public :\n      void getdata()\n      {\n          cin>>title;\n          cin>>price;\n      }\n};\nclass books :: public publication\n{\n   private :\n      int pagecount;\n   public :\n      void getdata()\n      {\n          cin>>pagecount;\n      }\n\n};\nclass tape :: public publication\n{\n   private :\n      int playing_time;\n   public :\n      void getdata()\n      {\n          cin>>playing_time;\n      }\n};
23929
oh crap i know this one    hang on     think think   an algorithm is a repeated process like converting binary to decimal and back.  but i can't think of one for finding the union sorry
42271
Pseudocode:\n\n// in a single statement\n(home_number AND (NOT office_number)) OR ((NOT home_number) AND office_number)\n\nNote: the above statement is the equivalent of an XOR logic statement, using AND and NOT
390615
Mn is close, but there are 2 errors:\n\n1) There is no len() function.  Use strlen() instead of len().\n\n2) He didn't allocate enough memory for the sprintf to fit the entire result string in the buffer.  The line needs room to store the &#92;n (or in windows, 2 chars - cr and lf ) in addition to the null terminator.  So, his code needs to add 2 instead of 1 to the length calculation.  \n\nTaking this a little further, the number of chars should be multiplied by the sizeof(t_char), which MIGHT NOT be 1 byte if the code is destined to use unicode.\n\nChances are, this is ascii, so the multiplication is unnecessary, but it is better to be safe than sorry.  Besides, if this was production code, you'd want to be able to use the same code in both places without any need to change it.  Nothing worse than having to go back and recalculate buffer manipulation code during a port.\n\nThe above subtleties demonstrate precisely how and why it is so very easy to make a mistake in c/c++, leading to a buffer underallocation or overwrite, and hence a security hole.
647017
Take out the equals sign after "limit". E.g.\n\nSELECT * FROM news ORDER BY time DESC limit 5
553275
Here you go\nhttp://www.thefreecountry.com/compilers/cpp.shtml\n///