Shannon-Fano implementation in C++

/*
 * Compress text file by using Shannon-Fano (No real compression,
 * just get the 0101 code)
 *
 * Author: bonep
 * Last update: 20120425
 *
 * Please free feel to use this code in any way
 *
 * Compile:
 * linux> c++ Shannon-Fano.cpp
 *
 * Usage:
 * linux> ./a.out
 * (the input text file is hardcoded as text1.txt)
 */

#include <stdio.h>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

#define MAX_CHAR 256

using namespace std;

/*
 * Define SymbolCode Class
 */
class SymbolCode {
private:
   char symbol;
   int frequency;
   string code;
public:
   SymbolCode( char in_symbol, int in_frequency );
   char getSymbol( void );
   int getFrequency( void );
   string getCode( void );
   void addCode( string in_code );
};

SymbolCode::SymbolCode( char in_symbol, int in_frequency ) {
   symbol = in_symbol;
   frequency = in_frequency;
   code = "";
}

char SymbolCode::getSymbol( void ) {
   return symbol;
}

int SymbolCode::getFrequency( void ) {
   return frequency;
}

string SymbolCode::getCode( void ) {
   return code;
}

void SymbolCode::addCode( string in_code ) {
   code += in_code;
}
/*
 * End SymbolCode Class
 */

// store the symbol sorted by frequency of which frequency not zero
vector<SymbolCode> symbol;

// store the input frequency
char frequency[ MAX_CHAR ];

void printSymbolCode( SymbolCode in_symbol ) {
   cout << "Symbol: " << in_symbol.getSymbol();
   cout << " Freq: " << in_symbol.getFrequency();
   cout << " Code: " << in_symbol.getCode() << endl;
}

void shannonFano( int in_begin, int in_end ) {
   // not a valid parameters input
   if ( in_begin >= in_end ) {
      return;
   }

   // only 2 symbol left
   if ( in_begin == in_end - 1 ) {
      symbol.at( in_begin ).addCode( "0" );
      symbol.at( in_end ).addCode( "1" );
      return;
   }

   int highPtr = in_begin; // highPtr will go downward
   int lowPtr = in_end;
   int highSum = symbol.at( highPtr ).getFrequency();
   int lowSum = symbol.at( lowPtr ).getFrequency();

   // move the highPtr down and lowPtr up until highSum and lowSum close
   while ( highPtr != lowPtr - 1 ) {
      if ( highSum > lowSum ) {
         lowPtr --;
         lowSum += symbol.at( lowPtr ).getFrequency();
      } else {
         highPtr ++;
         highSum += symbol.at( highPtr ).getFrequency();
      }
   }

   int i;
   for ( i=in_begin; i<=highPtr; i++ ) {
      symbol.at( i ).addCode( "0" );
   }
   for ( i=lowPtr; i<=in_end; i++ ) {
      symbol.at( i ).addCode( "1" );
   }

   shannonFano( in_begin, highPtr );
   shannonFano( lowPtr, in_end );
}

int main () {
   FILE * pFile;
   int c;
   int n = 0;
   pFile = fopen("text1.txt","r");
   if (pFile==NULL) {
      perror ("Error opening file");
   } else {
      int i;
      for ( i=0; i<MAX_CHAR; i++ ) {
         frequency[ i ] = 0;
      }
      do {
         c = fgetc (pFile);
         if ( c != EOF ) {
            frequency[ c ] ++;
            printf( "%c", c );
         }
      } while (c != EOF);
      fclose (pFile);
   }

   // print the frequency information
   cout << endl << endl;
   int i;
   for ( i=0; i<MAX_CHAR; i++ ) {
      if ( frequency[ i ] != 0 ) {
         printf( "%d, %c: %d\n", i, i, frequency[ i ] );
      }
   }

   // insert and sort the symbol
   printf( "\n\n" );
   for ( i=0; i<MAX_CHAR; i++ ) {
      if ( frequency[ i ] != 0 ) {
         if ( symbol.empty() ) {
            SymbolCode newSymbol( i, frequency[ i ] );
            symbol.push_back( newSymbol );
         } else {
            int j;
            vector<SymbolCode>::iterator it;
            it = symbol.begin();
            for ( j=0; j<symbol.size(); j++ ) {
               if ( frequency[ i ] >= symbol[ j ].getFrequency() ) {
                  SymbolCode newSymbol( i, frequency[ i ] );
                  symbol.insert( it, newSymbol );
                  break;
               } else if ( j == symbol.size() - 1 ) {
                  SymbolCode newSymbol( i, frequency[ i ] );
                  symbol.push_back( newSymbol );
                  break;
               }
               it ++;
            }
         }
      }
   }

   shannonFano( 0, symbol.size() - 1 );
  
   printf( "\n\n" );
   for_each( symbol.begin(), symbol.end(), printSymbolCode );

   return 0;
}