Re: How can i print the element poped from a generic STACK

[Larry Hazel <lhazel@mindspring.com>]

The procedore pop is a procedure.  It does not return a value.  You tried to
call it as a function.

Larry

jordan wrote:
> 
> Dear all,
> i want to ask that how can i print the element poped from a generic
> STACK.
> i have write the following code:
> =====================================================
> with TEXT_IO;
> use TEXT_IO;
> 
> procedure sample is
> 
> generic
>  SIZE : POSITIVE;
>  type ITEM is private;
> package STACK is
>  procedure PUSH(E : in ITEM);
>  procedure POP (E : out ITEM);
> end STACK;
> 
> package body STACK is
>  type TABLE is array (POSITIVE range <>) of ITEM;
>  SPACE : TABLE(1..SIZE);
>  INDEX : NATURAL := 0;
> 
>  procedure PUSH(E : in ITEM) is
>  begin
>   INDEX := INDEX + 1;
>   SPACE(INDEX) := E;
>  end PUSH;
> 
>  procedure POP(E : out ITEM) is
>  begin
>   E := SPACE(INDEX);
>   INDEX := INDEX - 1;
>  end POP;
> end STACK;
> 
>  package stackOfInt is new STACK(100, INTEGER);
>  use stackOfInt;
> 
>  package INT_IO is new TEXT_IO.INTEGER_IO(INTEGER);
>  use INT_IO;
> 
>  i : Integer;
> 
> begin
> 
>  stackOfInt.push(20);
> 
>  Put(stackOfInt.pop(i));            <------------- error!!!
> 
> end sample;
> 
> ==============================================
> i want to print the element of integer 20 on the screen, how can i do??
> is my implementation wrong???