Help with malloc and a complex struct

Dear C programmers,

I am having some serious issues when trying to dynamically allocate memory for a complex (at least to me) struct I need to use in order to input experimental data into my program.

The data consists of a number of trajectory clusters, each with a number of trajectories, each one of these defined by an x,y,z point over a number of timesteps. In addition, I assign different rgb colors for each cluster and other small details. The problem is that I do not know the number of clusters, trajectories, or timesteps until I read in the data file. Hence the need for dynamic allocation.

The structs I came up with to handle my data are:

Code:

typedef struct _timestepType {                
    int id;
    float x,y,z; 
} timestepType;

typedef struct _trajectoryType {
    timestepType *timestep;                    
} trajectoryType;

typedef struct _clusterType {
    float r,g,b;                           
    trajectoryType *trajectory;       
} clusterType;

clusterType *Cluster;

I.e., I work with objects that look like the following

Code:

Cluster[i].r
Cluster[i].trajectory[j].timestep[k].x

I confess that, even after a good dose of online tutorials, I am still very confused as to how to handle the dynamic memory allocation of something like this. A search in this forum showed me some posts with somewhat similar issues, but I am afraid I am still quite in the dark.

Could anyone help me out with this?

Thanks very much,

mc61

you should allocate memory for each pointer
starting with cluster

Code:

Cluster = malloc(ClusterNumber * sizeof *Cluster);

then for each member of this array you will allocate the memory for trajectory member

Code:

for(i=0;i<ClusterNumber ;i++)
{
   Cluster[i].trajectory = malloc (trajectoryNumber * sizeof *Cluster[i].trajectory );
   /* initialize here each member of Cluster[i].trajectory array */
}

and so on

Dear vart,

Thank you so very much!

mc61