/* File: CExamples/OO_pgm_in_C_new/stack_with_delete.h */

/* This is the abstract data object; initialize by calling clone on an actual stack
                                     (eg, see array_stack_without_new.c, main2.c)
                                     remove by calling delete_stack */
typedef struct stackstruct
  { void *objptr; /* address of data structure */

    /* abstract methods;
       the actual data structure of the stack is accessed as self->objptr
       In C++ self is the keyword this; self is from Smalltalk */
    int (*is_empty)(struct stackstruct* self); /* returns 0 if *self is empty */
    void(*push)    (int, struct stackstruct* self);
    int (*pop)     (struct stackstruct* self);

    /* object manipulation */
    struct stackstruct* (*clone) (const struct stackstruct* self); /* make a copy */
    void                (*delete_stack) (struct stackstruct* self); /* delete object memory */
  } stack,  *stackptr;