Rational3: The Implementation File

The implementation file includes definitions for the public member functions and external convenience functions. Notice that the definitions for the member functions use the scope resolution operator (::) so that they are defined within the Rational class.

//
// rational3.C
//
// Defining the class rational 
//   -- third attempt, separate compilation
// 
// by A.B. Maccabe  2/27/97
//

#include "rational3.h"


// Constructors
Rational::Rational( int n = 0, int d = 1 ) {
    num = n;
    denom = d;
}

// I/O
void Rational::read( istream &in ) {
    char slash;
    in >> num >> slash >> denom;
}

void Rational::write( ostream &out ) {
    out << num << '/' << denom;
}

// arithmetic
Rational Rational::neg( ) {
    return Rational( -num, denom );
}

Rational Rational::add( Rational rat ) {
    return Rational( num*rat.denom + denom*rat.num, denom*rat.denom );
}

Rational Rational::sub( Rational rat ) {
    return add( rat.neg() );
}

Rational Rational::mpy( Rational rat ) {
    return Rational( num*rat.num, denom*rat.denom );
}

Rational Rational::div( Rational rat ) {
    return Rational( num*rat.denom, denom*rat.num );
}


// define overloaded operators
Rational operator +( Rational r1, Rational r2 ) {
    return r1.add(r2);
}

ostream & operator <<( ostream &os, Rational r ) {
    r.write( os );
    return os;
}

istream & operator >>( istream &is, Rational &r ) {
    r.read( is );
    return is;
}