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// Fig. 8.19: hugeint1.cpp
// HugeInt member-function and friend-function definitions.
#include <cctype> // isdigit function prototype
#include <cstring> // strlen function prototype
#include "hugeint1.h" // HugeInt class definition
// default constructor; conversion constructor that converts
// a long integer into a HugeInt object
HugeInt::HugeInt( long value )
{
// initialize array to zero
for ( int i = 0; i <= 29; i++ )
integer[ i ] = 0;
// place digits of argument into array
for ( int j = 29; value != 0 && j >= 0; j-- ) {
integer[ j ] = value % 10;
value /= 10;
} // end for
} // end HugeInt default/conversion constructor
// conversion constructor that converts a character string
// representing a large integer into a HugeInt object
HugeInt::HugeInt( const char *string )
{
// initialize array to zero
for ( int i = 0; i <= 29; i++ )
integer[ i ] = 0;
// place digits of argument into array
int length = strlen( string );
for ( int j = 30 - length, k = 0; j <= 29; j++, k++ )
if ( isdigit( string[ k ] ) )
integer[ j ] = string[ k ] - '0';
} // end HugeInt conversion constructor
// addition operator; HugeInt + HugeInt
HugeInt HugeInt::operator+( const HugeInt &op2 )
{
HugeInt temp; // temporary result
int carry = 0;
for ( int i = 29; i >= 0; i-- ) {
temp.integer[ i ] =
integer[ i ] + op2.integer[ i ] + carry;
// determine whether to carry a 1
if ( temp.integer[ i ] > 9 ) {
temp.integer[ i ] %= 10; // reduce to 0-9
carry = 1;
} // end if
// no carry
else
carry = 0;
}
return temp; // return copy of temporary object
} // end function operator+
// addition operator; HugeInt + int
HugeInt HugeInt::operator+( int op2 )
{
// convert op2 to a HugeInt, then invoke
// operator+ for two HugeInt objects
return *this + HugeInt( op2 );
} // end function operator+
// addition operator;
// HugeInt + string that represents large integer value
HugeInt HugeInt::operator+( const char *op2 )
{
// convert op2 to a HugeInt, then invoke
// operator+ for two HugeInt objects
return *this + HugeInt( op2 );
} // end operator+
// overloaded output operator
ostream& operator<<( ostream &output, const HugeInt &num )
{
int i;
for ( i = 0; ( num.integer[ i ] == 0 ) && ( i <= 29 ); i++ )
; // skip leading zeros
if ( i == 30 )
output << 0;
else
for ( ; i <= 29; i++ )
output << num.integer[ i ];
return output;
} // end function operator<<
/**************************************************************************
* (C) Copyright 1992-2003 by Deitel & Associates, Inc. and Prentice *
* Hall. All Rights Reserved. *
* *
* DISCLAIMER: The authors and publisher of this book have used their *
* best efforts in preparing the book. These efforts include the *
* development, research, and testing of the theories and programs *
* to determine their effectiveness. The authors and publisher make *
* no warranty of any kind, expressed or implied, with regard to these *
* programs or to the documentation contained in these books. The authors *
* and publisher shall not be liable in any event for incidental or *
* consequential damages in connection with, or arising out of, the *
* furnishing, performance, or use of these programs. *
*************************************************************************/
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