包体和主程序。简单赋值 (Ada)
Package bodies and main programs. Simple assignment (Ada)
我卡在 Ada 里了。我应该创建一个具有特定 Flag_Type 的包，可以写入和读取以打印一个简单的标志。我想我已经设法使包广告和包主体 adb 正确，但我在主程序的命令上遇到了困难。
首先是第一个，输出应该是这样的：
Enter the flag name: Italys flag
Enter the flag height: 2
Enter the stripes width: 3
Enter the flags colors: GWR
Italys flag
+---------+
|GGGWWWRRR|
|GGGWWWRRR|
+---------+
现在，我的包裹 ADS 如下所示：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
package Flagdrawer is
type Flag_Type is private;
procedure Get(Item: out Flag_Type);
procedure Put(Item: in Flag_Type);
private
type Flag_Type is
record
Flag_Name: String(1..20);
L : Integer;
Flag_Height : Integer;
Flag_Width : Integer;
Flag_Colors : String(1..3);
end record;
end Flagdrawer;
我的包体是这样的：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
package body Flagdrawer is
procedure Get(Item: out Flag_Type) is
begin
Get_Line(Item.Flag_Name, Item.L);
Get(Item.Flag_Height);
Get(Item.Flag_Width);
Get(Item.Flag_Colors);
end Get;
procedure Put(Item: in Flag_Type) is
Real_Width : Integer;
begin
Real_Width := Item.Flag_Width *3;
Put(Item.Flag_Name(1..Item.L));
New_Line;
Put("+");
for I in 1..Real_Width loop
Put("-");
end loop;
Put_Line("+");
for J in 1..Item.Flag_Height loop
Put("!");
for K in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(1));
end loop;
for L in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(2));
end loop;
for M in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(3));
end loop;
Put_Line("!");
end loop;
Put("+");
for I in 1..Real_Width loop
Put("-");
end loop;
Put_Line("+");
end Put;
end Flagdrawer;
然后我非常缺少的主程序如下所示：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
begin
Put_line("Enter the flags name (1): ");
Put_Line("Enter the flags height (2): ");
Put_Line("Enter the stripes' width (3): ");
Put_Line("Enter the RGB for the flag's colors (4): ");
Get(F);
New_Line;
Put(F);
end Tenta_Flagdrawah;
我只习惯于具有一个特定输入的赋值，比如说 Get(F)，其中 F 是 Flag_Type，现在它分布在多个变量上，我不知道如何合并它们。
过去我从这里得到了很好的回应，有没有人可以给我一些提示，告诉我我错在哪里？我知道我的主程序严重缺乏，但我不知道如何编码。
在此先感谢您的帮助！
编辑
我找到了一个（有点）有效的解决方案，它在我直接交给西蒙赖特的这个主程序中被注释掉了，因为我不太明白你的声明是什么意思。我把它们放在我的 MP 中，我不断得到 "actual for item must be a variable"。我尝试使用 Item.Name 代替，但它声称其前缀无效。你觉得我哪里做错了？
主程序.adb
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Natural;
Stripe_Width : in Natural;
Colors : in Color_String) is
begin
Put("Enter the flag's name: ");
Get(Name);
Put("Enter the flag's height: ");
Get(Height);
end Get;
begin
-- Put_line("Enter the flags name (1): ");
-- Put_Line("Enter the flags height (2): ");
-- Put_Line("Enter the stripes' width (3): ");
-- Put_Line("Enter the RGB for the flag's colors (4): ");
-- Get(F);
New_Line;
Put(F);
end Tenta_Flagdrawah;
方法同上一个post（参见），只是添加用户输入逻辑：
main.adb
with Ada.Text_IO; use Ada.Text_IO;
procedure Main is
Stripes : constant array (Natural range <>) of Character := "GWR";
Stripe_Width : constant Positive := 3;
Width : constant Natural := 2 + Stripes'Length * Stripe_Width;
Height : constant Natural := 2 + 2;
type Screen_X is new Natural range 0 .. Width - 1;
type Screen_Y is new Natural range 0 .. Height - 1;
-------------
-- Pattern --
-------------
function Pattern (X : Screen_X; Y : Screen_Y) return Character is
Is_Border_LR : constant Boolean :=
X = Screen_X'First or else X = Screen_X'Last;
Is_Border_TB : constant Boolean :=
Y = Screen_Y'First or else Y = Screen_Y'Last;
begin
if Is_Border_LR and Is_Border_TB then
return '+';
elsif Is_Border_LR then
return '|';
elsif Is_Border_TB then
return '-';
else
return Stripes (Integer (X - Screen_X'First - 1) / Stripe_Width);
end if;
end Pattern;
begin
-- The Render loop.
for Y in Screen_Y loop
for X in Screen_X loop
Put (Pattern (X, Y));
end loop;
New_Line;
end loop;
end Main;
输出
$ ./main
+---------+
|GGGWWWRRR|
|GGGWWWRRR|
+---------+
你的很多麻烦是Get程序；它实现了各个字段的所有文本输入，而不参考主程序正在做什么。
一般来说，在 Flag 之类的 abstract data type 中执行 I/O 并不是好的做法；在调用程序中更好地完成它。 （我可以看出 Put 会很尴尬）。
您可以读取主程序中的参数并提供给Get,
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Natural;
Stripe_Width : in Natural;
Colors : in Color_String);
这意味着要制定包装规范（抱歉，我忍不住要整理一下）
package Flagdrawer is
type Flag_Type is private;
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Positive;
Stripe_Width : in Positive;
Colors : in Color_String);
procedure Put(Item: in Flag_Type);
private
type Flag_Type is
record
Name : String (1 .. 20);
Name_Len : Natural;
Height : Positive;
Stripe_Width : Positive;
Colors : Color_String;
end record;
end Flagdrawer;
并在包体中实现 Get 作为
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Positive;
Stripe_Width : in Positive;
Colors : in Color_String) is
begin
-- Don’t exceed the 20-character limit on the stored Name
Item.Name_Len := Natural'Min (Item.Name'Length, Name'Length);
Item.Name (1 .. Item.Name_Len) := Name (Name'First .. Item.Name_Len);
Item.Height := Height;
Item.Stripe_Width := Stripe_Width;
Item.Colors := Colors;
end Get;
主程序是
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
begin
Put("Enter the flags name: ");
-- Need a declare block so that Name
-- is as long as the user input
declare
Name : constant String := Get_Line;
Height : Positive;
Stripe_Width : Positive;
Colors : Flagdrawer.Color_String;
begin
Put("Enter the flag's height: ");
Get (Height);
Put("Enter the stripes' width: ");
Get (Stripe_Width);
Put("Enter the RGB for the flag's colors: ");
Get (Colors);
Get(F,
Name => Name,
Height => Height,
Stripe_Width => Stripe_Width,
Colors => Colors);
end;
New_Line;
Put(F);
end Tenta_Flagdrawah;
我卡在 Ada 里了。我应该创建一个具有特定 Flag_Type 的包，可以写入和读取以打印一个简单的标志。我想我已经设法使包广告和包主体 adb 正确，但我在主程序的命令上遇到了困难。
首先是第一个，输出应该是这样的：
Enter the flag name: Italys flag
Enter the flag height: 2
Enter the stripes width: 3
Enter the flags colors: GWR
Italys flag
+---------+
|GGGWWWRRR|
|GGGWWWRRR|
+---------+
现在，我的包裹 ADS 如下所示：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
package Flagdrawer is
type Flag_Type is private;
procedure Get(Item: out Flag_Type);
procedure Put(Item: in Flag_Type);
private
type Flag_Type is
record
Flag_Name: String(1..20);
L : Integer;
Flag_Height : Integer;
Flag_Width : Integer;
Flag_Colors : String(1..3);
end record;
end Flagdrawer;
我的包体是这样的：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
package body Flagdrawer is
procedure Get(Item: out Flag_Type) is
begin
Get_Line(Item.Flag_Name, Item.L);
Get(Item.Flag_Height);
Get(Item.Flag_Width);
Get(Item.Flag_Colors);
end Get;
procedure Put(Item: in Flag_Type) is
Real_Width : Integer;
begin
Real_Width := Item.Flag_Width *3;
Put(Item.Flag_Name(1..Item.L));
New_Line;
Put("+");
for I in 1..Real_Width loop
Put("-");
end loop;
Put_Line("+");
for J in 1..Item.Flag_Height loop
Put("!");
for K in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(1));
end loop;
for L in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(2));
end loop;
for M in 1..Item.Flag_Width loop
Put(Item.Flag_Colors(3));
end loop;
Put_Line("!");
end loop;
Put("+");
for I in 1..Real_Width loop
Put("-");
end loop;
Put_Line("+");
end Put;
end Flagdrawer;
然后我非常缺少的主程序如下所示：
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
begin
Put_line("Enter the flags name (1): ");
Put_Line("Enter the flags height (2): ");
Put_Line("Enter the stripes' width (3): ");
Put_Line("Enter the RGB for the flag's colors (4): ");
Get(F);
New_Line;
Put(F);
end Tenta_Flagdrawah;
我只习惯于具有一个特定输入的赋值，比如说 Get(F)，其中 F 是 Flag_Type，现在它分布在多个变量上，我不知道如何合并它们。
过去我从这里得到了很好的回应，有没有人可以给我一些提示，告诉我我错在哪里？我知道我的主程序严重缺乏，但我不知道如何编码。
在此先感谢您的帮助！
编辑
我找到了一个（有点）有效的解决方案，它在我直接交给西蒙赖特的这个主程序中被注释掉了，因为我不太明白你的声明是什么意思。我把它们放在我的 MP 中，我不断得到 "actual for item must be a variable"。我尝试使用 Item.Name 代替，但它声称其前缀无效。你觉得我哪里做错了？
主程序.adb
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Natural;
Stripe_Width : in Natural;
Colors : in Color_String) is
begin
Put("Enter the flag's name: ");
Get(Name);
Put("Enter the flag's height: ");
Get(Height);
end Get;
begin
-- Put_line("Enter the flags name (1): ");
-- Put_Line("Enter the flags height (2): ");
-- Put_Line("Enter the stripes' width (3): ");
-- Put_Line("Enter the RGB for the flag's colors (4): ");
-- Get(F);
New_Line;
Put(F);
end Tenta_Flagdrawah;
方法同上一个post（参见
main.adb
with Ada.Text_IO; use Ada.Text_IO;
procedure Main is
Stripes : constant array (Natural range <>) of Character := "GWR";
Stripe_Width : constant Positive := 3;
Width : constant Natural := 2 + Stripes'Length * Stripe_Width;
Height : constant Natural := 2 + 2;
type Screen_X is new Natural range 0 .. Width - 1;
type Screen_Y is new Natural range 0 .. Height - 1;
-------------
-- Pattern --
-------------
function Pattern (X : Screen_X; Y : Screen_Y) return Character is
Is_Border_LR : constant Boolean :=
X = Screen_X'First or else X = Screen_X'Last;
Is_Border_TB : constant Boolean :=
Y = Screen_Y'First or else Y = Screen_Y'Last;
begin
if Is_Border_LR and Is_Border_TB then
return '+';
elsif Is_Border_LR then
return '|';
elsif Is_Border_TB then
return '-';
else
return Stripes (Integer (X - Screen_X'First - 1) / Stripe_Width);
end if;
end Pattern;
begin
-- The Render loop.
for Y in Screen_Y loop
for X in Screen_X loop
Put (Pattern (X, Y));
end loop;
New_Line;
end loop;
end Main;
输出
$ ./main
+---------+
|GGGWWWRRR|
|GGGWWWRRR|
+---------+
你的很多麻烦是Get程序；它实现了各个字段的所有文本输入，而不参考主程序正在做什么。
一般来说，在 Flag 之类的 abstract data type 中执行 I/O 并不是好的做法；在调用程序中更好地完成它。 （我可以看出 Put 会很尴尬）。
您可以读取主程序中的参数并提供给Get,
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Natural;
Stripe_Width : in Natural;
Colors : in Color_String);
这意味着要制定包装规范（抱歉，我忍不住要整理一下）
package Flagdrawer is
type Flag_Type is private;
subtype Color_String is String (1 .. 3);
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Positive;
Stripe_Width : in Positive;
Colors : in Color_String);
procedure Put(Item: in Flag_Type);
private
type Flag_Type is
record
Name : String (1 .. 20);
Name_Len : Natural;
Height : Positive;
Stripe_Width : Positive;
Colors : Color_String;
end record;
end Flagdrawer;
并在包体中实现 Get 作为
procedure Get (Item : out Flag_Type;
Name : in String;
Height : in Positive;
Stripe_Width : in Positive;
Colors : in Color_String) is
begin
-- Don’t exceed the 20-character limit on the stored Name
Item.Name_Len := Natural'Min (Item.Name'Length, Name'Length);
Item.Name (1 .. Item.Name_Len) := Name (Name'First .. Item.Name_Len);
Item.Height := Height;
Item.Stripe_Width := Stripe_Width;
Item.Colors := Colors;
end Get;
主程序是
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Flagdrawer; use Flagdrawer;
procedure Tenta_Flagdrawah is
F: Flag_Type;
begin
Put("Enter the flags name: ");
-- Need a declare block so that Name
-- is as long as the user input
declare
Name : constant String := Get_Line;
Height : Positive;
Stripe_Width : Positive;
Colors : Flagdrawer.Color_String;
begin
Put("Enter the flag's height: ");
Get (Height);
Put("Enter the stripes' width: ");
Get (Stripe_Width);
Put("Enter the RGB for the flag's colors: ");
Get (Colors);
Get(F,
Name => Name,
Height => Height,
Stripe_Width => Stripe_Width,
Colors => Colors);
end;
New_Line;
Put(F);
end Tenta_Flagdrawah;