array init in constructor

[josh]

Hi, which is the way to init a static array inside a constructor
function?
i.e. if I had to init ---> int x[] = {100,200}

[=?iso-8859-1?q?Erik_Wikstr=F6m?=]

On 10 Apr, 11:30, "josh" <[e-mail]:

Hi, which is the way to init a static array inside a constructor
function?
i.e. if I had to init ---> int x[] = {100,200}

If the member is static it is not initialized in the constructor, but
outside the class declaration.

struct Foo
{
static int x[];
};

int Foo::x[] = {1,2};

--
Erik Wikström

[josh]

On 10 Apr, 13:07, "Erik Wikström" <[e-mail]:

On 10 Apr, 11:30, "josh" <[e-mail]:

Hi, which is the way to init a static array inside a constructor
function?
i.e. if I had to init ---> int x[] = {100,200}

If the member is static it is not initialized in the constructor, but
outside the class declaration.

struct Foo
{
static int x[];

};

int Foo::x[] = {1,2};

--
Erik Wikström

so if I want in a class declaration to have an array like
int x[] not static I must make it as pointer and than in a
constructor init as:

class T
{
int *p;
T();
}

T::T()
{
p = new int[3];
p[0] = 100;
p[1] = 200;
p[2] = 300;
}

but this is so boring...

[James Kanze]

On Apr 10, 1:21 pm, "josh" <[e-mail]:

so if I want in a class declaration to have an array like
int x[] not static I must make it as pointer and than in a
constructor init as:

class T
{
int *p;
T();

}

T::T()
{
p = new int[3];
p[0] = 100;
p[1] = 200;
p[2] = 300;
}

but this is so boring...

Why the pointer? You can do exactly the same thing with "int
array[ 3 ] ;". For initialization, there are two possibilities:
wrap it in a struct,

class T
{
struct A { int a[ 3 ] ; } ;
A data ;
T() ;
}

static T::A initData = {{ 100, 200, 300 }} ;

T::T()
: data( initData )
{
}

or use copy from a static array:

class T
{
int a[ 3 ] ;
T() ;
}

T::T()
{
static int const init[3] = { 100, 200, 300 } ;
std::copy( init, init+3, a ) ;
}

--
James Kanze (GABI Software) email:ja*********@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[josh]

On 10 Apr, 18:56, "James Kanze" <[e-mail]:

On Apr 10, 1:21 pm, "josh" <[e-mail]:

so if I want in a class declaration to have an array like
int x[] not static I must make it as pointer and than in a
constructor init as:
class T
{
int *p;
T();

}
T::T()
{
p = new int[3];
p[0] = 100;
p[1] = 200;
p[2] = 300;
}
but this is so boring...

Why the pointer? You can do exactly the same thing with "int
array[ 3 ] ;". For initialization, there are two possibilities:
wrap it in a struct,

class T
{
struct A { int a[ 3 ] ; } ;
A data ;
T() ;
}

static T::A initData = {{ 100, 200, 300 }} ;

T::T()
: data( initData )
{
}

or use copy from a static array:

class T
{
int a[ 3 ] ;
T() ;
}

T::T()
{
static int const init[3] = { 100, 200, 300 } ;
std::copy( init, init+3, a ) ;
}

--
James Kanze (GABI Software) email:[e-mail]
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

why always static?