// Fig. 8.8: hugeint1.cpp 
// Member and friend function definitions for class HugeInt
#include <string.h>
#include "Hugeint2.h"

// Conversion constructors
HugeInt::HugeInt( long val )
{
   int i; 

   for ( i = 0; i <= MAX_INDEX; i++ )
      integer[ i ] = 0;   // initialize array to zero

   if ( val < 0 ) {
     sign = -1;
     val = -val;
     }
   else 
     sign = 1;

   for ( i = MAX_INDEX; val != 0 && i >= 0; i-- ) {
      integer[ i ] = val % 10;
      val /= 10;
   }

}

HugeInt::HugeInt( const char *string )
{
   int i, j;

   for ( i = 0; i <= MAX_INDEX; i++ )
      integer[ i ] = 0;

   if ( string[0] == '-' ) {// assuming non-null string.
     sign = -1;
     string++;
     }
   else 
     sign = 1;

   for ( i = SIZE - strlen( string ), j = 0; i <= MAX_INDEX; i++, j++ )
      integer[ i ] = string[ j ] - '0';
}

// Addition
HugeInt HugeInt::operator+( HugeInt &op2 )
{ // incorrect for now
   HugeInt temp;
   int carry = 0;

   for ( int i = MAX_INDEX; i >= 0; i-- ) {
      temp.integer[ i ] = integer[ i ] + 
                          op2.integer[ i ] + carry;

      if ( temp.integer[ i ] > 9 ) {
         temp.integer[ i ] %= 10;
         carry = 1;
      }
      else
         carry = 0;
   }

   return temp;
}

HugeInt HugeInt::operator+( int op2 )
   { return *this + HugeInt( op2 ); }

HugeInt HugeInt::operator+( const char *op2 )
   { return *this + HugeInt( op2 ); }

// subtraction
HugeInt HugeInt::operator-( HugeInt &op2 ) 
  { return HugeInt((long)0); } // stub for now }

HugeInt HugeInt::operator-( int op2 )
   { return *this - HugeInt( op2 ); }

HugeInt HugeInt::operator-( const char *op2 )
   { return *this - HugeInt( op2 ); }

// negation
void HugeInt::negate() {
  sign = -sign;
  }

// the friends
HugeInt operator+( int op1, HugeInt& op2 ) 
   { return op2 + op1; }
  
HugeInt operator-( int op1, HugeInt& op2 ) 
   { return op2 - op1; }
  
HugeInt abs( HugeInt& op ) {
  HugeInt ans = op;
  if ( ans.sign == -1 ) ans.negate();
  return ans;
  }

ostream& operator<<( ostream &output, HugeInt &num )
{
   int i;

   for ( i = 0; ( num.integer[ i ] == 0 ) && ( i <= MAX_INDEX ); i++ )
      ; // skip leading zeros

   if ( i == SIZE )
      output << 0;
   else {
      if ( num.sign == -1 ) output << "-";
      for ( ; i <= MAX_INDEX; i++ )
         output << num.integer[ i ];
      }

   return output;
}