Thread: Constructor Initialization/operator overloading

I've got a couple of questions, I'm just a little curious as to what is going on, I am doing a workshop for teach yourself c++ in 21 days. My code works but it differs from the answers.

First of all I am to write a class, its functions and a single variable easy enough, I am also
to implement 2 constructors a copy constructor and prefix and postfix operators. Then I am to
change the 1 variable to be on the free store, and fix everything accordingly.

The questions I have are regarding the initialization stage of the constructors and the prefix/
postfix operator functions.

In my contructors before using the free store I have...

Code:

SimpleCircle::SimpleCircle():
itsRadius(5)
{}

SimpleCircle::SimpleCircle(USHORT r):
itsRadius(r)
{}

Default initializes to 5. The answers are the same, but...

after the free store I have...

Code:

SimpleCircle::SimpleCircle():
itsRadius(new USHORT(5))
{}

SimpleCircle::SimpleCircle(USHORT r):
itsRadius(new USHORT(r))
{}

The answer is...

Code:

SimpleCircle::SimpleCircle()
{
	itsRadius = new USHORT(5);
}

SimpleCircle::SimpleCircle(USHORT r)
{
	itsRadius = new USHORT(r);
}

Is there any difference between the 2 methods? Preferred or otherwise? Like I said my code works.


Onto the prefix/postfix.

Before the free store change I had...

Code:

const SimpleCircle& SimpleCircle::operator++()
{
    ++itsRadius;
    return *this;
}

const SimpleCircle SimpleCircle::operator++(int)
{
    SimpleCircle temp;
    ++itsRadius;
    return temp;
}

The answer is...

Code:

const SimpleCircle& SimpleCircle::operator++()
{
    ++(itsRadius);
    return *this;
}

const SimpleCircle SimpleCircle::operator++(int)
{
    SimpleCircle temp(*this);
    ++(itsRadius);
    return temp;
}

Whats with the parenthesis? and do you have to put (*this) ?

Ok after the free store change I have...

Code:

const SimpleCircle& SimpleCircle::operator++()
{
    ++(*itsRadius);
    return *this;
}

const SimpleCircle SimpleCircle::operator++(int)
{
    SimpleCircle temp;
    ++(*itsRadius);
    return temp;
}

The * to dereference itsRadius but in the answer...

Code:

const SimpleCircle& SimpleCircle::operator++()
{
    ++(itsRadius);
    return *this;
}

const SimpleCircle SimpleCircle::operator++(int)
{
    SimpleCircle temp(*this);
    ++(itsRadius);
    return temp;
}

The (*this) is there still, but itsRadius is not dereferenced! I tried it like this and got
strange output so is there a mistake in the answers or could I have missed something else
entirely?

Thanks

Thanks, is (*this) the same as = *this?