initilize array member's size in object constructor?

[crichmon]

Is there away to initialize an array's size through constructor
initialization?

Right now I have

///////////////
class foo
{
string bar[20];
public:
foo();
}

////
foo::foo()
{
};


////////////////

could something be done like

///////////////
class foo
{
string bar[];
public:
foo();
}

////
foo::foo(): bar[20]
{
};


////////////////

Any help?

thanks,
crichmon

 

[Alf P. Steinbach]

* crichmon:

could something be done like

///////////////
class foo
{
string bar[];
public:
foo();
}

////
foo::foo(): bar[20]
{
};

class Foo
{
private:
std::vector<std::string> bar;
public:
Foo(): bar(20) {}
};

 

[Rolf Magnus]

Is there away to initialize an array's size through constructor
initialization?

Right now I have

///////////////
class foo
{
string bar[20];
public:
foo();
}

////
foo::foo()
{
};

class foo
{
string* bar;
public:
foo();
//don't forget copy construction/assignment/destructor
};

foo::foo()
: bar(new string[20])
{
}

////////////////

could something be done like

///////////////
class foo
{
string bar[];
public:
foo();
}

////
foo::foo(): bar[20]
{
};

No. Why would you want that? Note that a class has a size that is fixed
at compile time, so you couldn't put a non-constant expression between
the brackets anyway. And in the other case, you wouldn't gain anything.

 

[John Harrison]

Is there away to initialize an array's size through constructor
initialization?

Right now I have

///////////////
class foo
{
string bar[20];
public:
foo();
}

////
foo::foo()
{
};


////////////////

could something be done like

///////////////
class foo
{
string bar[];
public:
foo();
}

////
foo::foo(): bar[20]
{
};


////////////////

Any help?

thanks,
crichmon

Use a vector

class foo
{
vector<string> bar;
public:
foo();
}

////
foo::foo(): bar(20)
{
};

It's what vectors are for.

john

 

[Alf P. Steinbach]

* John Harrison:

Use a vector

class foo
{
vector<string> bar;
public:
foo();
}

Here should be a semicolon.

////
foo::foo(): bar(20)
{
};

Here should not be a semicolon.

I gather my reply to the same posting had not yet reached your
news-server.

 

[Fraser Ross]

A nontype template parameter can be used.

template <int val=20>
class foo
{
string bar[val];
};

foo<30> test();

Fraser.

 

[Rolf Magnus]

A nontype template parameter can be used.

template <int val=20>
class foo
{
string bar[val];
};

foo<30> test();

<Nitpick>
Note that 'test' is a declaration of a function that returns a foo<30>.
I don't think you actually wanted that.
</Nitpick>