question on constructor from tutorial

[chrisben]

as the example

1.CRectangle rectb; // right
2. CRectangle rectb(); // wrong!

3. CRectangle rectb = new CRectangle;
4. CRectangle rectb = new CRectangle();

question 1
is 4 same as 3?

question 2
2 is wrong, buy why? I can compile codes wihtout prob. What is called when rectb() is called?

Thanks

[Disch]

1) Correct. Creates an object of type CRectangle, and uses the default constructor.

2) Wrong. It will compile okay, but doesn't do what you expect. It does not create a CRectangle object. Instead it is a function prototype which returns a CRectangle. Much like how int foo(); declares a function called foo.

3) Wrong because rectb is not a pointer. However assuming that was a typo.. CRectangle* rectb = new CRectangle; is correct. Creates a CRectangle object dynamically using the default constructor.

4) Wrong for same reason number 3 is wrong. But assuming that was a typo: CRectangle* rectb = new CRectangle(); is correct and does what you'd expect -- the same thing as #3.

[chrisben]

crystal clear. thank you very much