Simplifying constructors

[BobMorane]

Hello everyone,

In an internet class I am following, we had to make a "fraction" class, that is, a class to handle rational numbers. To do this, I created the three following constructors:

Rational::Rational(): m_numerateur(0), m_denominateur(1)
{
}

Rational::Rational(int numerateur): m_numerateur(numerateur), m_denominateur(1)
{
}

Rational::Rational(int numerateur, int denominateur): m_numerateur(numerateur), m_denominateur(denominateur)
{
    if(denominateur == 0) // We check that the denominator is different than 0.
    {
        std::cout << "Erreur: le dénominateur doit être un entier différent de 0!" << std::endl;
    }
    else
    {
        if(denominateur < 0)
        {
            m_denominateur = -m_denominateur;
            m_numerateur = -m_numerateur;
        }
        else
        {
            // The fraction is already either of the form a(x,y), x,y>0 or of the form a(x,y), x<0, y>0.
        }
    }
}

After the homework was completed, the teacher wrote that those three constructors could be simplified into one constructor.

How is this possible?

Thank you for your time,

Eric

[ne555]

http://www.cplusplus.com/doc/tutorial/functions/ (Default values in parameters)

[BobMorane]

Thanks a lot ne555, works well!!