Pointers in c how it works

int size = 256; //<-- Can be whatever you need (doesn't have to be a hard coded constant, could be some variable that's evaluated at run time)

//Using malloc/free
int *iArray;
iArray = (int *) malloc(size*sizeof(int));  //Allocate (requires size in bytes, hence the sizeof() call)

//To check if valid and take appropriate action
if(iArray == NULL)
{
  printf("Error: Failed to allocated required memory.");
  exit(1);
}

//... Use
free(iArray);                               //Deallocate when done