Reinitializing object

[hamsterman]

Hi,
Is there a way I could call a constructor for already constructed object?
I have something like this:

int global_val=0;
struct A: public A{
    //members...
    A(){}
    A(int i){
        global_val=i;
    }
    ~A(){
        global_val=0;
    }
};
int main(){
    A* obj=new A;
    //lots of code...
    *obj=A(15);
    return 0;
}

This doesn't work, becouse this code creates another object, copies its members and destroys it, so global_val will be 0 in the end.
Of course I could do this with a function Set(int i) but I wanted to know if there is another way.

thanks for your replies

[Disch]

Is there a way I could call a constructor for already constructed object?

No. One object gets one constructor called once. This keeps things very simple. You technically can side-step this by using placement new, but you really shouldn't -- it'd be a horrible, horrible thing to do.

Your best bet is a Set type function.

[Bazzy]

You can overload the ( ) or = operators to have a syntax similar to the constructor

[kempofighter]

since global_val is a global variable, why bother using a structure instance to change it? Why not just write
global_val = 5;

In this case you just need to create a reasonable interface for your struct or class. Create mutator member functions that can modify its state. That is what public interfaces are for. It has a default assignment operator or you can write your own if necessary depending on whether this class needs one to be written. You can certainly create a reset member function to reset the objects state to its initial values.