text: #ifndef  __ARRAY_STACK_H__
  #define __ARRAY_STACK_H__
  
  #define INITIAL_CAPACITY            100
  
  extern int arr_err;
  
  typedef struct arr_stack_s
  {
      int *arr;
      int len;
      int capacity;
  } arr_stack_t;
  
  int arr_pop(arr_stack_t *stack);
  int arr_look(arr_stack_t stack);
  int arr_append(arr_stack_t *stack, int val);
  int arr_print_stack(arr_stack_t stack);
  
  arr_stack_t *arr_init_stack(void);
  void arr_clear_stack(arr_stack_t **stack);
  arr_stack_t *astack_cpy(arr_stack_t *src);
  
  #endif // __ARRAY_STACK_H__
  