That's the easy part, I need to instance objects without doing something like:
Object a;
Object b;
8,000 times over..
EDIT: I didn't see that post above when i wrote this.
Instancing an Object with a Dynamically created name?
Quote:Original post by MaulingMonkey
*** Source Snippet Removed ***
Obviously, a few more layers of wrapping should be used. I'm just showing the door :-).
Edit: But, this is assuming you want to create objects - if you're just looking to look them up, see the post bellow :-p.
Yes, you could use a map, and you'd probably be generating iterative strings to create your objects - but if you're doing that, wouldn't it be simpler to use a 1-dimensional array? The index itself acts like the object's name for you.
@OP: Do you really need (possibly) hundreds of unique variable identifiers?
I'm suprised that no one else noticed, but your example code shows that you are trying to use pointers, but you don't know what they are. A pointer is like a variable without a name. I am getting sleepy so I can't elaborate but you independantly came up with the concept of a pointer, and should be proud. However you probably don't need to use pointers directly. I would look into a container, such as std::vector or map, as it will handle all of the memory management for you. I suggest getting yourself a good C++ book.
Quote:Original post by Crashman
How do you instance an Object named by a variable and then call functions from it?
ie.
int i = 0;
while(till doomsday)
{
Object i;
++i;
}
3.Set();
15.Set();
Something along the lines of that.
#include
std::vector objects;
int i = 0;
while( !doomsday ) {
objects.push_back( object() );
++i;
}
objects[69].Set();
objects[420].Set();
^^ me. Using a std::vector as shown above gives you the syntax you want without all the overhead of a std::map.
EDIT: you actually don't need i if doomsday is an exterior function.
EDIT: you actually don't need i if doomsday is an exterior function.
Author
Quote:Original post by stylin
@OP: Do you really need (possibly) hundreds of unique variable identifiers?
Maybe, I'm going to have the program generate a 20x20x20 matrix of objects, and I need each object to have 1 of a few colors randomly selected at generation. I also need to check the neighbors of each object.
Quote:Original post by Anonymous Poster
#include
std::vector objects;
int i = 0;
while( !doomsday ) {
objects.push_back( object() );
++i;
}
objects[69].Set();
objects[420].Set();
Unless I declare what type of data it's going to hold when I create a vector, like-
std::vector<string> objects;
The compiler gives me an error. [headshake] So how exactly do I store them in the vector?
Quote:Original post by Crashman
The compiler gives me an error. [headshake] So how exactly do I store them in the vector?
The anonymous post cut my angle brackets out. It should have read:
std::vector< object > objects;Quote:... I'm going to have the program generate a 20x20x20 matrix of objects, and I need each object to have 1 of a few colors randomly selected at generation. I also need to check the neighbors of each object.
Look into boost::multi_array, or store your objects in a 1 dimensional std::vector, something like this:
#include <vector>const unsigned int WIDTH = 20; // cube dimensionsconst unsigned int HEIGHT = 20;const unsigned int DEPTH = 20;// two methods to generate your objectsvoid object_generation_method1( std::vector< object > & );void object_generation_method2( std::vector< object > & );// function to retrieve an object @ location ( x,y,z ) in the cubeobject & get_object( std::vector< object > &, int x, int y, int z );int main() { // fill array with enough objects for a [WIDTH][HEIGHT][DEPTH] cube std::vector< object > cube( WIDTH*HEIGHT*DEPTH, object() ); object_generation_method2( cube ); // set colors ... // do something useful with the cube}void object_generation_method1( std::vector< object > & cube ) { for( int i=0; i<WIDTH ) for( int j=0; j<HEIGHT ) for( int k=0; k<DEPTH ) { cube[ ( i*HEIGHT + j ) * DEPTH + k ].set_color( /* random number */ ); ... // other useful stuff }}void object_generation_method2( std::vector< object > & cube ) { std::vector< object >::iterator it = cube.begin(); while( it != cube.end() ) { (*it++).set_color( /* random number */ ); ... // other useful stuff } return;}object & get_object( std::vector< object > & cube, int x, int y, int z ) { return cube[ ( x*HEIGHT + y ) * DEPTH + z ];}With the get_object function, it's trivial to check neighboring objects. Let me know if this is still unclear, and I'll try to explain a little better.
EDIT: fixed typo.
[Edited by - stylin on October 23, 2005 5:44:31 PM]
Author
I do have one question about the iterators and that last function (two questions?). Is there a way to delete a portion of a vector without using an Iterator? and I tried making a function return an object (reference) like-
but it threw a syntax error at me. And the reason I wanted to know a more direct way of removing/accessing vectors is because when I made a 20x20x20 cube, it bombed out on me.
Quote:object & get_object( std::vector< object > & cube, int x, int y, int z ) {
return cube[ ( x*HEIGHT + y ) * DEPTH + z ];
}
but it threw a syntax error at me. And the reason I wanted to know a more direct way of removing/accessing vectors is because when I made a 20x20x20 cube, it bombed out on me.
Quote:Original post by Crashman
I do have one question about the iterators and that last function (two questions?). Is there a way to delete a portion of a vector without using an Iterator?
Ya know, you can put std::vector into a search engine and find numerous pages containing the information your looking for, that is the members, implementation and syntax of the vector class, and you'll probably get a better explaination than you would here anyway.
Quote: ... and I tried making a function return an object (reference) like-Quote:object & get_object( std::vector< object > & cube, int x, int y, int z ) {
return cube[ ( x*HEIGHT + y ) * DEPTH + z ];
}
but it threw a syntax error at me. And the reason I wanted to know a more direct way of removing/accessing vectors is because when I made a 20x20x20 cube, it bombed out on me.
Ya know, saying things like "it threw a syntax error at me" and "it bombed out on me" doesn't give anybody *any* indication of what's going on in your code. The sooner you realise this, the better off you'll be.
Have a nice day.
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