How to import and output several files in voro++?

Question

This script makes me import a single file with the 'con.import()' function and it makes output a single file with 'con.print_costum()' function, now i want to import several files at the same time and each input files makes ma an output file, how can i do ?

int main() {
// Create a container with the geometry given above, and make it
// non-periodic in each of the three coordinates. Allocate space for
// eight particles within each computational block.
container con(x_min,x_max,y_min,y_max,z_min,z_max,n_x,n_y,n_z,
        false,false,false,8);

// Add a cylindrical wall to the container
wall_cylinder cyl(0,0,0,0,0,1,10);
con.add_wall(cyl);

// Import the particles from a file
con.import("rpack0.dmp");

// Do a custom output routine that outputs the particle IDs and
// positions, plus the volume
con.print_custom("%i %q %v","packing.custom");}

I did this but what about the Output?

// Import the particles from a files
DIR *di;
char *ptr1,*ptr2;
int retn;
struct dirent *dir;
di = opendir("."); // specify the directory name
if (di)
{
    while ((dir = readdir(di))!= NULL)
    {
        ptr1=strtok(dir->d_name,".");
        ptr2=strtok(NULL,".");
        if(ptr2!=NULL)
        {
            retn=strcmp(ptr2,".dmp");
            if(retn==0)
            {
                con.import(ptr1);
                
            }

        }
    }
    //closedir(di);
}
return(0);