Ada - Stacked records?

Question

Basically I'm trying stack a record (1 record is 2 string variables, and there's 3 of them but I'd like to stack at least 1 for the time being). I'm thinking the setup would like something like this for my algorithm:

Client: Values are given to strings in record, procedures for stack are called (ie, push, pop, display) Package: Record is declared, items are pushed/popped onto stack, display stack.

I'm having trouble in general. I tried keeping it all local. It does open the file and read in the strings (tried it out reading in an integer value, works fine), this I have tested in the client program using a similar setup (instead of a record I stored it to a string of length 40). However when I'd go to output it all I'd get is a bunch of random symbols (such as ╤cß≈Ä), no words like the file contained.

Here are my code fragments:

Package spec:

StackMaximum: constant integer := 10;
   TYPE StackItem IS Record
str1: string (1..20);
str2: string (1..20);
 end record;

   type Stack is PRIVATE

    PROCEDURE Push (Item: IN StackItem; AStack: IN OUT Stack);
    PROCEDURE display (AStack : in Stack);

Package body:

procedure Push (Item: in StackItem;
            AStack: in out Stack) is
begin
 if AStack.Top < StackMaximum then
     AStack.Top := AStack.Top + 1;
     AStack.Store(AStack.Top) := Item;
 else
     raise StackOverflow;
 end if;
END Push;

    procedure display(AStack: in stack) is
  BEGIN

     FOR I IN 1..AStack.Top LOOP
        Put(AStack.Store(I.lastname));
     END LOOP;
  END display;

    PRIVATE
    type int_arry is array (1..StackMaximum) of StackItem;
    type Stack is record
        Store: int_arry;
        Top: integer range 0..StackMaximum;
    END RECORD;

Client:

Lt:           Integer;
New_Stack2:    Stack;
A:            StackItem;
Stackitems:   Ada.Text_IO.File_Type;

   Get_Line(File => Stackitems, Item => A.str1, Last => Lt);
   Get_Line(File => Stackitems, Item => A.str2, Last => Lt);

   Push(A, New_Stack1);
   display(New_Stack1);

File (Only contains "This..var."):

This is the test input for the file var.

Any suggestions for what I'm doing wrong with this part? Also here's my other setup where I kept it all local:

Client:

Lt:           Integer;
AB:           String(1..40);
New_Stack2:    Stack;
A:            StackItem;
Stackitems:   Ada.Text_IO.File_Type;

begin

   Get_Line(File => Stackitems, Item => AB, Last => Lt);

   Put(item=> AB);

end;

This is what got me all those symbols. But it is reading in the file, I just have no idea why I'm getting the bad output.

That's the file name; try changing the content to 8-bit ASCII text. — trashgod
It has to be in that format. The file was made in Ada GIDE if that's any help. — Lance

Simon Wright Simon Wright · Accepted Answer · 2011-11-27T08:40:47

Perhaps in your definition of type Stack you should initialize Top to 0?

type Stack is record
   Store: int_arry;
   Top: Integer range 0 .. StackMaximum := 0;
end record;;

Ada - Stacked records?

2 Answers