C/C++ Users Group Library 1996 July/C-C++ Users Group Library July 1996.iso/vol_400/445_01/fracti10/fraction.cpp

C/C++ Source or Header | 1994-11-05 | 6.0 KB | 295 lines

// General Fraction class - also handles Mixed Numbers & Decimals


// M\Cooper
// 3425 Chestnut Ridge Rd.
// Grantsville, MD 21536-9801
// --------------------------
// Email:  [e-mail]


#include <iostream.h>
#include <stdlib.h>
#include <string.h>

#define MAXLEN 30
#define ARGCOUNT 4
#define OPERATOR_ERROR 5
#define WRONG_NO_OF_ARGS 2
#define MAXIMUM(x,y) (x>=y) ? x:y
#define SLASH '/'
#define DASH '-'
#define TERM1 argv[1]
#define OP   *argv[2]
#define TERM2 argv[3]
#define POSITIVE 0
#define NEGATIVE 1

const long SCALING_FACTOR = 1000;

enum boolean {FALSE, TRUE};

void input_error();

class Fraction
    {
    protected:
        long numerator;
        long denominator;
        double decimal_equivalent;

        long integer_part;
        long part_numerator;
        long part_denominator;

    public:
        Fraction()
            { numerator = 0; denominator = 1;
              part_numerator = 0; part_denominator = 1;
              decimal_equivalent = 0.; integer_part = 0;}

        Fraction( long num, long denom )
            {
              numerator =   num;
              denominator = denom;
              decimal_equivalent = (double)numerator/(double)denominator;
              part_numerator = 0; part_denominator = 1;
              integer_part = 0;
            }
        Fraction( double decimal )
            {
             numerator =   (long) (SCALING_FACTOR * decimal);
             denominator = SCALING_FACTOR;
             decimal_equivalent = decimal;
             part_numerator = 0; part_denominator = 1;
             integer_part = 0;
             }


        void show()
            {
            cout << "The result: "
                  << numerator << SLASH << denominator << endl;

            if( integer_part )
                {
                cout << "Converted to a mixed number: " << integer_part;
                    if( part_numerator )
                        cout << "-" << part_numerator << SLASH << part_denominator
                              << endl;
                }
            cout << "Decimal equivalent = " << decimal_equivalent << endl;
            }

        Fraction operator + (Fraction fr)  // addition
        {
        long num, denom;

             if( denominator == fr.denominator )
                 {
                 num =   numerator + fr.numerator;
                 denom = denominator;
                 }
             else
                 {
                 num   = numerator * fr.denominator
                         + fr.numerator * denominator;
                 denom = denominator * fr.denominator;
                 }

             return ( Fraction(num,denom) );
        }

        Fraction operator - (Fraction fr)    // subtraction
        {
        long num, denom;

            if( denominator == fr.denominator )
                {
                num =   numerator - fr.numerator;
                denom = denominator;
                }
            else
                {
                num   = numerator * fr.denominator
                        - fr.numerator * denominator;
                denom = denominator * fr.denominator;
                }

            return  ( Fraction(num,denom) );
        }

        Fraction operator * (Fraction fr)     // multiplication
        {
            long num =   numerator * fr.numerator;
            long denom = denominator * fr.denominator;

            return ( Fraction(num,denom) );
         }

         Fraction operator / (Fraction fr)   // division
         {
             long num =   numerator * fr.denominator;
             long denom = denominator * fr.numerator;

             return ( Fraction(num,denom) );
         }

        Fraction parse( char * );
        boolean isfactor( long, long );
        long gcf( long, long );
        void reduce();
        void improper_to_proper();
        void proper_to_improper();

     };

boolean Fraction::isfactor( long number, long factor )
    {
    if( !(number % factor) )
        return (TRUE);
    else
        return (FALSE);
    }

long Fraction::gcf( long num, long denom )
    {
        long smaller,
              larger,
              temp;

            larger = MAXIMUM(num,denom);
            smaller = temp = (num==larger) ? denom : num;

            while( temp )
                if( isfactor( smaller, temp ) && isfactor( larger, temp ) )
                    break;
                else
                    temp--;

            return (temp);
    }

void Fraction::reduce()
    {
    long temp;
    int sign = POSITIVE;

        if( numerator < 0)    //negative fraction
            { sign = NEGATIVE; numerator *= -1; }

        while( (temp = gcf( numerator, denominator ) ) >1 )
            { numerator /= temp; denominator /= temp; }

        if( sign )
            numerator *= -1;   //change back to negative

        return;
        }


void Fraction::improper_to_proper()
    {
    if( labs(numerator) >= denominator )
        {
        integer_part = numerator / denominator;
        part_numerator = labs( numerator - denominator * integer_part) ;
        part_denominator = denominator;
        }
    else
        {
        integer_part = 0;
        part_numerator = numerator;
        part_denominator = denominator;
        }
    }

void Fraction::proper_to_improper()
    { numerator = numerator + integer_part*denominator; }

Fraction Fraction::parse( char *token )
{
    char *denom_ptr,
          *dash_ptr;
    Fraction temp;

    if ( (dash_ptr = strchr( ++token, DASH )) != NULL )
            // skip 1st char., in case minus sign...
            {
            temp.integer_part = atol( --token );  // renormalize
            token = ++dash_ptr;
            }
     else --token;   // renormalize

     if( (denom_ptr = strchr( token, SLASH )) != NULL )
         {
         temp.numerator = atol( token );
         temp.denominator = atol( ++denom_ptr );
         temp.proper_to_improper();
         temp.decimal_equivalent =
         (double)temp.numerator/(double)temp.denominator;
         }
     else
         temp = atof( token );

     return (temp);
}

Fraction operation_on( Fraction& t1, Fraction& t2, char oper )
{
   Fraction temp;

     switch (oper)
     {
         case '+':
             temp = t1 + t2;
             break;
         case '-':
             temp = t1 - t2;
             break;
         case '*':
             temp = t1 * t2;
             break;
         case '/':
             temp = t1 / t2;
             break;
         default:
             input_error();
             exit( OPERATOR_ERROR );
     }

      return (temp) ;
}



void main( int argc, char* argv[] )
     {

     Fraction term1,
                 term2,
                 result;

     if( argc != ARGCOUNT )
         input_error();

        term1 = term1.parse( TERM1 );
        term2 = term2.parse( TERM2 );
        result = operation_on( term1, term2, OP );

     result.reduce();
     result.improper_to_proper();
     result.show();

     }

     void input_error()
     {
         cout << endl
                << "Format: fraction aaa/bbb <operator> ccc/ddd" << endl
                << "                             or" << endl
                << "             AAA-aaa/bbb <operator> CCC-ccc/ddd" << endl;

          exit( WRONG_NO_OF_ARGS );
     }