Maps

[armen_shlang]

Here is an example by author:
---------------------------------------------
/* Filename: diction.cpp
Author: Br. David Carlson
Date: July 14, 1999
Last Revised: December 23, 2001

This interactive program creates a map (table), where each entry
is a pair containing a word and its definition. Thus the map is
a small dictionary. The program then allows the user to repeatedly
look up the meaning of words.

In the code, change CTRL z to CTRL d for Linux.
*/

and the website if your keen to see the real code....
http://cis.stvincent.edu/html/tutori...maps/maps.html

and finally the code with the small change I made that gave me an error at line number 88...I don't understand why the compiler wont compile. All I did was add another member to the private section called recNum. The error says that it cannot convert char[] to class LineClass...

#include <iostream>
#include <map>
using namespace std;

const int LineMax = 72;

const int NULLCHAR = '\0';

typedef char LineType[LineMax];

class LineClass
   {
   private:
	  LineType Info;	
	  int recordNum;
 public:
      LineClass(void);
      LineClass(LineType Str, int recNum);
      void GetLine(LineType Line) const;
	  int  GetRecordNum() const {return recordNum;};
   };

LineClass::LineClass(void)
   {
   Info[0] = NULLCHAR;
   recordNum = 0;
   }

LineClass::LineClass(LineType Str, int recNum)
:	recordNum(recNum)
   {
   strcpy(Info, Str);
   }

void LineClass::GetLine(LineType Line) const
   {
   strcpy(Line, Info);
   }

bool operator<(LineClass LHS, LineClass RHS)
   {
   LineType Left, Right;

   LHS.GetLine(Left);
   RHS.GetLine(Right);

   if (strcmp(Left, Right) < 0)
      return true;
   else
      return false;
   }


// Function prototypes:
void LoadData(map<LineClass, LineClass> & Dictionary);
void Lookup(LineType Target, map<LineClass, LineClass> & Dictionary);

int main(void)
   {
   map<LineClass, LineClass> Dictionary;
   LineType Target;

   LoadData(Dictionary);

   // Change to CTRL d for Linux:
   cout << "Enter word to look for (or CTRL z to quit): ";
   cin >> Target;
   while (! cin.fail())
      {
      Lookup(Target, Dictionary);
      // Change to CTRL d for Linux:
      cout << "Enter word to look for (or CTRL z to quit): ";
      cin >> Target;
      }

   return 0;
   }

void Lookup(LineType Target, map<LineClass, LineClass> & Dictionary)
   {
   map<LineClass, LineClass>::iterator p;
   LineType Meaning;
   p = Dictionary.find(LineClass(Target));      // <===========LINE88
   //p is pointing to the found target object
   if (p != Dictionary.end())
      {
      p->second.GetLine(Meaning); //second is the mapped value so the mapped value is also a class.
      cout << "Meaning is: " << Meaning << endl;
      }
   else
      cout << "Word not found" << endl;
   }

void LoadData(map<LineClass, LineClass> & Dictionary)
//the dictionary is holding a list/map of lineClass'es
   {
   // Note the 2 different ways of creating a pair to insert:
   Dictionary.insert(pair<LineClass, LineClass>(LineClass("hot", 1),
      LineClass("having a high temperature", 1)));
   Dictionary.insert(make_pair(LineClass("cold",1),
      LineClass("having a low temperature" ,1)));
   Dictionary.insert(make_pair(LineClass("jog" ,1),
      LineClass("run slowly", 1)));
   Dictionary.insert(make_pair(LineClass("intelligent", 1),
      LineClass("smart", 1)));
   Dictionary.insert(make_pair(LineClass("register" ,1),
      LineClass("a high-speed storage location on a computer's CPU chip", 1)));
   }

[Philip Nicoletti]

 p = Dictionary.find(LineClass(Target));

You do not have a constructor for LineClass that just takes a LineType
as a first argument. You either need to provide an int argument or
provide a default one in the construtor.

   p = Dictionary.find(LineClass(Target,0));      // <===========LINE88

// OR

      LineClass(LineType Str, int recNum=0);

[JohnW@Wessex]

Your LineClass has constructors for zero or two parameters. The line in error is only supplying one.