Let's consider a queue implemented with type t_queue_tab, a two-index array.

This queue can only be manipulated using the standard enqueue() and dequeue() functions, which are well written.

Reminder: the t_queue_tab type is defined as follows:

#define MAX 30
typedef struct s_queue_tab
{
   int values[MAX];
   int first;
   int last;
} t_queue_tab;