Access struct members as if they are a single array?

Question

I have two structures, with values that should compute a pondered average, like this simplified version:

typedef struct
{
  int v_move, v_read, v_suck, v_flu         


        

Answer 1

If all members a guaranteed to be of type int you can use a pointer to int and increment it:

int *value = &(values.v_move);
int *quantity = &(quantities.qtt_move);
int i;
average = 0;
// although it should work, a good practice many times IMHO is to add a null as the last member in struct and change the condition to quantity[i] != null.
for (i = 0; i < sizeof(quantities) / sizeof(*quantity); i++)
    average += values[i] * quantity[i];

(Since the order of members in a struct is guaranteed to be as declared)