C++ Struct in array, help!
I have an iPhone app that used to use an array of several thousand small objects for its data source. Now, I am trying to make it use C++ Structs, to improve performance. I have written the struct, and put it in "Particle.h":
    typedef struct{
       double changeX;
       double changeY;
       double x;
       double y;
    }ParticleStruct;

Then, I imported "Particle.h", and attempted to define the array:
    struct ParticleStruct particles[];   ///Size will be determined later, this declaration is to make the declaration visible to the entire class...
On this line, however, I get the error: "Array type has incomplete element type".
Everything else compiles fine, as far as I can tell, and I am sure that "Particle.h" has been imported before the declaration.
Any ideas?
C++ Struct in array, help!
===

I have an iPhone app that used to use an array of several thousand small objects for its data source. Now, I am trying to make it use C++ Structs, to improve performance. I have written the struct, and put it in "Particle.h":
    typedef struct{
       double changeX;
       double changeY;
       double x;
       double y;
    }ParticleStruct;

Then, I imported "Particle.h", and attempted to define the array:
    struct ParticleStruct particles[];   ///Size will be determined later, this declaration is to make the declaration visible to the entire class...
On this line, however, I get the error: "Array type has incomplete element type".
Everything else compiles fine, as far as I can tell, and I am sure that "Particle.h" has been imported before the declaration.
Any ideas?