Initializing array of pointers to an object in a class constructor

[Francesco S. Carta]

Francesco S. Carta ha scritto:

[OT]
Are you the same Christian Hackl that runs on the bobsleighs?
Just out of curiosity
[/OT]

Why, of course I am. All Austrian bobsledders write C++ programs in
their spare time.

Ahah! I suspected that!

(j/k)

OK, fine ;-)

Cheers!

 

[John]

might I ask...

SomeClass::SomeClass() :
myObjPtrs(123)
{
for(int i=0; i<123; i++)
{
myObjPtrs = std::shared_ptr<MyObj>(new MyObj);
}
}

What is " : myObjPtrs(123)" for?
Is it the same as:

SomeClass::SomeClass()
{
myObjPtrs.resize(123); // (or reserve in case of push_back)
......
}

because with the first version "123" can't be dynamic number but only
defined at compile time...

 

[Francesco S. Carta]

might I ask...

SomeClass::SomeClass() :
myObjPtrs(123)
{
for(int i=0; i<123; i++)
{
myObjPtrs = std::shared_ptr<MyObj>(new MyObj);
}
}

What is " : myObjPtrs(123)" for?
Is it the same as:

SomeClass::SomeClass()
{
myObjPtrs.resize(123); // (or reserve in case of push_back)
.....
}

Yes and no: both resize() and the ctor initialization list (" :
myObjPtrs(123)" in this case) change the size of the vector (they
actually add objects to it) while reserve() just allocates space for
them so that there will be no reallocation when pushing back elements up
to the reserved count of elements.

because with the first version "123" can't be dynamic number but only
defined at compile time...

You can pass that argument to the constructor if you want, such as:
SomeClass::SomeClass(int n) : myObjPtrs(n) {}