rational.cpp

c++程序设计讲义 cppprograming 含源码

// Program rational.cpp

#include <iostream>
#include <string>
#include "rational.h"

using namespace std;

// default constructor
Rational::Rational() {
	SetNumerator(0);
	SetDenominator(1);
}

// (numer, denom) constructor
Rational::Rational(int numer, int denom) {
	SetNumerator(numer);
	SetDenominator(denom);
}

// Rational: copy constructor
Rational::Rational(const Rational &r) {
    int a = r.GetNumerator();
    int b = r.GetDenominator();
    SetNumerator(a);
    SetDenominator(b);
}

// Rational: destructor
Rational::~Rational() {
    // no body needed
}

// get the numerator
int Rational::GetNumerator() const {
	return NumeratorValue;
}

// get the denominator
int Rational::GetDenominator() const {
	return DenominatorValue;
}

// set the numerator
void Rational::SetNumerator(int numer) {
	NumeratorValue = numer;
}

// set the denominator
void Rational::SetDenominator(int denom) {
	if (denom != 0) {
		DenominatorValue = denom;
	}
	else {
		cerr << "Illegal denominator: " << denom
		<< "using 1" << endl;
		DenominatorValue = 1;
	}
}

// adding Rationals
Rational Rational::Add(const Rational &r) const {
	int a = GetNumerator();
	int b = GetDenominator();
	
	int c = r.GetNumerator();
	int d = r.GetDenominator();
	
	return Rational(a*d + b*c, b*d);
}

// subtracting Rationals
Rational Rational::Sub(const Rational &r) const {
    int a = GetNumerator();
    int b = GetDenominator();
    
    int c = r.GetNumerator();
    int d = r.GetDenominator();
    
    return Rational(a*d - b*c, b*d);
}

// multiplying Rationals
Rational Rational::Multiply(const Rational &r) const {
	int a = GetNumerator();
	int b = GetDenominator();
	
	int c = r.GetNumerator();
	int d = r.GetDenominator();
	
	return Rational(a*c, b*d);
}

// dividing Rationals
Rational Rational::Divide(const Rational &r) const {
    int a = GetNumerator();
    int b = GetDenominator();
    
    int c = r.GetNumerator();
    int d = r.GetDenominator();
    
    return Rational(a*d, b*c);
}

// Rational: assignment operator
Rational& Rational::operator=(const Rational &r) {
    int a = r.GetNumerator();
    int b = r.GetDenominator();
    
    SetNumerator(a);
    SetDenominator(b);
    
    return *this;
}

/*
void Rational::operator=(const Rational &r) {
    int a = r.GetNumerator();
    int b = r.GetDenominator();
    
    SetNumerator(a);
    SetDenominator(b);
    
    return;
}
*/


// inserting a Rational
void Rational::Insert(ostream &sout) const {
	sout << GetNumerator() << '/' << GetDenominator();
	return;
}

// extracting a Rational
void Rational::Extract(istream &sin) {
	int numer;
	int denom;
	char slash;
	sin >> numer >> slash >> denom;
	SetNumerator(numer);
	SetDenominator(denom);
	return;
}

// adding Rationals
Rational operator+(const Rational &r, const Rational &s) {
	return r.Add(s);
}

// subtracting Rationals
Rational operator-(const Rational &r, const Rational &s) {
    return r.Sub(s);
}

// multiplying Rationals
Rational operator*(const Rational &r, const Rational &s) {
	return r.Multiply(s);
}

// dividing Rationals
Rational operator/(const Rational &r, const Rational &s) {
    return r.Divide(s);
}

// inserting a Rational
ostream& operator<<(ostream &sout, const Rational &r) {
	r.Insert(sout);
	return sout;
}

// extracting a Rational
istream& operator>>(istream &sin, Rational &r) {
	r.Extract(sin);
	return sin;
}

int main() {
    Rational r;
    Rational s;
    cout << "Enter 1st rational number (a/b): ";
    cin >> r;
    cout << "Enter 2nd rational number (a/b): ";
    cin >> s;
    Rational tr(r);
    Rational ts = s;
    Rational tts;
    tts = s;
    ts = tts = r;
    Rational Sum = r + s;
    Rational Difference = r - s;
    Rational Product = r * s;
    Rational Ratio = r / s;
    cout << r << " + " << s << " = " << Sum << endl;
    cout << r << " - " << s << " = " << Difference << endl;
    cout << r << " * " << s << " = " << Product << endl;
    cout << r << " / " << s << " = " << Ratio << endl;
    return 0;
}