Ada初学者堆栈程序 [英] Ada beginner Stack program

问题描述

基本上，我有2个文件（.adb和.ads）。我是Ada的新手，还介绍了如何编译2个文件。该程序是一个基本的堆栈实现。编译.adb文件时出现此编译错误。

Basically, I have 2 files ( .adb and .ads). I am totally new to Ada and also how to compile 2 files. The program is of a basic stack implementation. I got this compile error when I compiled the .adb file.

$ gcc -c test_adt_stack.adb
abstract_char_stack.ads:22:01: end of file expected, file can have only one compilation unit

这两个文件我有：
abstract_char_stack.ads

-----------------------------------------------------------
package Abstract_Char_Stack is
  type Stack_Type is private;
  procedure Push(Stack : in out Stack_Type;
                 Item  : in Character);
  procedure Pop (Stack : in out Stack_Type;
                 Char  : out Character);
private
  type Space_Type is array(1..8) of Character;
  type Stack_Type is record
    Space : Space_Type;
    Index : Natural := 0;
  end record;
end Abstract_Char_Stack;
-----------------------------------------------------------
package body Abstract_Char_Stack is
----------------------------------------------
  procedure Push(Stack : in out Stack_Type;
                  Item : in Character) is
  begin
    Stack.Index := Stack.Index + 1;
    Stack.Space(Stack.Index) := Item;
  end Push;
--------------------------------------------
  procedure Pop (Stack : in out Stack_Type;
                 Char  : out Character) is
  begin
    Char := Stack.Space(Stack.Index);
    Stack.Index := Stack.Index - 1;
  end Pop;
--------------------------------------------
end Abstract_Char_Stack;

另一个是 test_adt_stack.adb

-----------------------------------------------------------
with Ada.Text_IO; use Ada.Text_IO;
with Abstract_Char_Stack; use Abstract_Char_Stack;
procedure Test_ADT_Stack is
  S1 : Stack_Type;
  S2 : Stack_Type;
  Ch : Character;
begin
  Push(S1,'H'); Push(S1,'E');  
  Push(S1,'L'); Push(S1,'L');
  Push(S1,'O');                          -- S1 holds O,L,L,E,H

  for I in 1..5 loop
    Pop(S1, Ch);  
    Put(Ch);                             -- displays OLLEH
    Push(S2,Ch); 
  end loop;                              -- S2 holds H,E,L,L,O

  New_Line;
  Put_Line("Order is reversed");

  for I in 1..5 loop
    Pop(S2, Ch);
    Put(Ch);                             -- displays HELLO
  end loop;

end Test_ADT_Stack;
-----------------------------------------------------------

我在做什么错？我只想编译它并显示它的功能。这是研究程序分配的一种方法。但是我无法使其编译或不知道我是否做对了。

What am I doing wrong? I just want to have it compile and display what it's supposed to do. This was a study the program kind of assignment. But I can't make it compile or don't know if I am doing it right.

推荐答案

问题是GNAT [而FCC GNAT是GCC使用的，IIRC]不允许在单个文件中使用多个编译单元。 （这是由于他们如何管理图书馆，但是对于初学者来说，这可能太详细了。）

The problem is that GNAT [and FSF GNAT is what GCC uses, IIRC] does not allow multiple compilation-units in a single file. (This is due to how they manage the library, but that is perhaps a bit too detailed for a beginner to worry about.)

解决方案，每个方案都需要自己的解决方案文件：

Solution, each of these needs its own file:

• Abstract_Char_Stack规范（ abstract_char_stack.ads ）


• Abstract_Char_Stack主体（ abstract_char_stack.adb ）


• Test_ADT_Stack [procedure]主体（ test_adt_stack。 adb ）

• Abstract_Char_Stack Specification (abstract_char_stack.ads)
• Abstract_Char_Stack Body (abstract_char_stack.adb)
• Test_ADT_Stack [procedure] body (test_adt_stack.adb)

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