DaniWeb Forum Index > Software Development > C++

C++ RSS

modifying the same member of many objects

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: May 2006

Posts: 38

Reputation: LieAfterLie is an unknown quantity at this point

Solved Threads: 2

LieAfterLie LieAfterLie is offline

Offline

Light Poster

modifying the same member of many objects

Oct 23rd, 2006

How would you change the same member of many objects of the same class (or structure if possible)?

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
struct point
{
    float x, y, z;
}
 
point a, b, c;
 
a.x += 20;  //
b.x += 20;  // now how would i do this in one statement?
c.x += 20;  //
struct point
{
    float x, y, z;
}

point a, b, c;

a.x += 20;  //
b.x += 20;  // now how would i do this in one statement?
c.x += 20;  //

I don't see how inheritance or polymorphism would apply, and as far as I know they don't work with structures anyway, and I really have no need of classes. So how would I change all point::x members universally regardless of how many or what objects use it?

•

Join Date: Jun 2005

Posts: 1,496

Reputation: WolfPack has a spectacular aura about

Solved Threads: 104

WolfPack

Offline

Mentally Challenged Mod.

Re: modifying the same member of many objects

Oct 23rd, 2006

How about declaring x as a static member of class point?

バルサミコ酢やっぱいらへんで

•

Join Date: May 2006

Posts: 38

Reputation: LieAfterLie is an unknown quantity at this point

Solved Threads: 2

LieAfterLie LieAfterLie is offline

Offline

Light Poster

Re: modifying the same member of many objects

Oct 23rd, 2006

Well I need each x member to have different instances, like this:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
struct point
{
    float x, y, z;
}
 
point a, b, c;
 
a.x = 10;
b.x = -50;
c.x = 2000.3258;
 
a.x += 20;  //
b.x += 20;  // now how would i do this in one statement?
c.x += 20;  //
struct point
{
    float x, y, z;
}

point a, b, c;

a.x = 10;
b.x = -50;
c.x = 2000.3258;

a.x += 20;  //
b.x += 20;  // now how would i do this in one statement?
c.x += 20;  //

and yet be able to modify them all, even if there were hundreds of instances of point.

•

Join Date: Oct 2006

Posts: 89

Reputation: TylerSBreton is an unknown quantity at this point

Solved Threads: 3

TylerSBreton TylerSBreton is offline

Offline

Junior Poster in Training

Re: modifying the same member of many objects

Oct 23rd, 2006

•

Originally Posted by LieAfterLie

Well I need each x member to have different instances, like this:
Help with Code Tags

C++ Syntax (Toggle Plain Text)
struct point
{
    float x, y, z;
}
 
point a, b, c;
 
a.x = 10;
b.x = -50;
c.x = 2000.3258;
 
a.x += 20;  //
b.x += 20;  // now how would i do this in one statement?
c.x += 20;  //
struct point { float x, y, z; } point a, b, c; a.x = 10; b.x = -50; c.x = 2000.3258; a.x += 20; // b.x += 20; // now how would i do this in one statement? c.x += 20; //
and yet be able to modify them all, even if there were hundreds of instances of point.

How about creating an array of points, then using a loop to traverse each element of the array?

•

Join Date: May 2006

Posts: 38

Reputation: LieAfterLie is an unknown quantity at this point

Solved Threads: 2

LieAfterLie LieAfterLie is offline

Offline

Light Poster

Re: modifying the same member of many objects

Oct 24th, 2006

Okay, I'll use a multidimesional array to store the 'objects'. I just thought it would be helpful if I could name them different things and use the default copy constructor/copy assignment constructor, like b = a; or point top (c);. Don't you think such a member-modifying feature should be added to C++? It would be awesome.