用褶皱画一本书的封面 (Ada)
Drawing a book's cover with folds (Ada)
我正在做一个作业，这个作业类似于这个站点上已经解决的标志包问题 ()
不过这次我需要画一个4折的书皮，如下图：
Book with folds at the breaking points: 3, 10, 15, 17.
Height = 2, Width = 20,
Title (string(1..100),
Author (string(1..50).
<Title>
<Author>
|--|------|----|-|---|
| | | | | |
| | | | | |
|--|------|----|-|---|
我在 exercise_bluebook_main.adb 的第 25 行遇到了很多问题，但最让我烦恼的是
exercise_bluebook_main.adb:25:11: expected type "Standard.Integer" exercise_bluebook_main.adb:25:11: found type "Breaking_Array" defined
at exercise_bluebook.ads:7
当我输出定义的数组时，为什么它需要一个标准整数？此外，我认为在主程序第 15 行的声明部分我遇到了麻烦，因为 :=get_line 已经被 "Title" 占用。你会如何解决这个问题，有人吗？
也许代码中的错误比这更多，我感谢所有建设性的输入！
我的 .ads 文件
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
package Exercise_BlueBook is
subtype Break_Points is integer range 1..20;
type Breaking_Array is array (1..4) of Break_Points;
type Book_Type is private;
procedure Get (Item: out Book_Type;
Title: in String;
Author: in String;
Width: in Integer;
Height: in Integer;
Break_Points: in Breaking_Array);
procedure Put (Item: in Book_Type);
private
type Book_Type is
record
Title : String(1..100);
Title_L : Integer;
Author : String(1..50);
Author_L : Integer;
Width : Integer;
Height : Integer;
Break_Points : Integer;
end record;
end Exercise_BlueBook;
我的包体adb文件
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
with Exercise_Bluebook; use Exercise_Bluebook;
package body Exercise_BlueBook is
procedure Get (Item: out Book_Type;
Title: in String;
Author: in String;
Width: in Integer;
Height: in Integer;
Break_Points: in Breaking_Array) is
begin
Item.Title_L := Integer'Min (Item.Title'Length, Title'Length);
Item.Title (1..Item.Title_L) := Title(Title'First .. Item.Title_L);
Item.Author_L := Integer'Min (Item.Author'Length, Author'Length);
Item.Author (1..Item.Author_L) := Author (Author'First .. Item.Author_L);
Item.Width := Width;
Item.Height := Height;
Item.Break_Points := Break_Points;
end Get;
procedure Put (Item: in Book_Type) is
begin
Put_Line(Item.Title(1..Item.Title_L));
Put_Line(Item.Author(1..Item.Author_L));
for H in 1..Item.Height loop
Put("!");
for I in 1..Item.Width loop
Put("-");
if I = Breaking_Array(1) then
Put("!");
elsif I = Breaking_Array(2) then
Put("!");
elsif I = Breaking_Array(3) then
Put("!");
elsif I = Breaking_Array(4) then
Put("!");
end if;
end loop;
Put_Line("!");
end loop;
end Put;
end Exercise_BlueBook;
我的主要程序
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
with Exercise_Bluebook; use Exercise_Bluebook;
procedure Exercise_BlueBook_Main is
B : Book_Type;
begin
Put("Enter the name of the book: ");
declare
Title : constant String := Get_Line; -- First Get_Line already taken
Author: constant String := Get_Line; -- How do I solve this for "Author"?
Width: Integer;
Height: Integer;
Break_Points : Exercise_BlueBook.Breaking_Array;
begin
Put("Enter the book's width: ");
Get(Width);
Put("Enter the book's height: ");
Get(Height);
Put("Enter the breaking points for the fold: ");
Get(Break_Points); -- Won't read this as an array?
Get(B,
Title => Title,
Author => Author,
Width => Width,
Height => Height,
Break_Points => Break_Points);
end;
New_Line;
Put(B);
end Exercise_BlueBook_Main;
Ada.Integer_Text_IO 包中的 Get 子程序将只读取一个整数。您可以通过添加循环来扩展它：
main.adb
with Ada.Text_IO; use Ada.Text_IO;
procedure Main is
generic
type Num is range <>;
type Arr is array (Integer range <>) of Num;
procedure Get (From : String; Item : out Arr);
---------
-- Get --
---------
procedure Get (From : String; Item : out Arr) is
package Num_IO is
new Ada.Text_IO.Integer_IO (Num);
Last : Integer := From'First - 1;
begin
for Idx in Item'Range loop
Num_IO.Get (From (Last + 1 .. From'Last), Item (Idx), Last);
end loop;
end Get;
subtype Break_Points is Integer range 1 .. 20;
type Breaking_Array is array (Integer range <>) of Break_Points;
procedure Get_Breaking_Array is
new Get (Break_Points, Breaking_Array);
BA : Breaking_Array (1 .. 4);
begin
Get_Breaking_Array (Get_Line, BA);
New_Line;
Put_Line("Result:");
for BP of BA loop
Put (BP'Image);
New_Line;
end loop;
exception
when Data_Error =>
Put_Line ("Error: Invalid data.");
when End_Error =>
Put_Line ("Error: Not enough elements.");
end Main;
输出（元素太多，只读取前4个）。
$ ./main
1 2 3 4 5 6
Result:
1
2
3
4
输出（元素太少）。
$ ./main
1 2 3
Error: Not enough elements.
输出（非数字数据）。
$ ./main
1 2 x 4
Error: Invalid data.
输出（元素值超出范围）。
$ ./main
1 2 3 100
Error: Invalid data.
就目前而言，主程序提示输入标题，然后为 Title 调用 Get_Line，然后为 Author 调用另一个 Get_Line。下面的数据是使用Gets读取的；工作的方式是读取字符，跳过白色 space 直到找到可能是数字一部分的内容，然后读取更多字符直到找到不能成为数字一部分的内容。
我们一直在推荐表格的原因
declare
Title : constant String := Get_Line;
是一个String是一个fixed-length字符数组；你怎么能提前知道要多长时间呢？其工作方式是所需的实际长度在 运行 时间由 Get_Line.
返回的初始化值的长度确定
您可以通过更改提示来解决缺少作者提示的问题："Enter the book’s name and the author’s name, hit RET after each:".
或者您可以嵌套它们：
Put("Enter the name of the book: ");
declare
Title : constant String := Get_Line;
begin
Put("Enter the author's name: ");
declare
Author: constant String := Get_Line;
Width: Integer;
Height: Integer;
Break_Points : Exercise_BlueBook.Breaking_Array;
begin
Put("Enter the book's width: ");
Get(Width);
Put("Enter the book's height: ");
Get(Height);
Put("Enter the breaking points for the fold: ");
现在我们来看看Break_Points。您需要用自己的 Get:
读取每个元素
for J in Break_Points'Range loop
Get(Break_Points(J));
end loop;
Get(B,
Title => Title,
Author => Author,
Width => Width,
Height => Height,
Break_Points => Break_Points);
end;
end;
我正在做一个作业，这个作业类似于这个站点上已经解决的标志包问题 (
不过这次我需要画一个4折的书皮，如下图：
Book with folds at the breaking points: 3, 10, 15, 17.
Height = 2, Width = 20,
Title (string(1..100),
Author (string(1..50).
<Title>
<Author>
|--|------|----|-|---|
| | | | | |
| | | | | |
|--|------|----|-|---|
我在 exercise_bluebook_main.adb 的第 25 行遇到了很多问题，但最让我烦恼的是
exercise_bluebook_main.adb:25:11: expected type "Standard.Integer" exercise_bluebook_main.adb:25:11: found type "Breaking_Array" defined at exercise_bluebook.ads:7
当我输出定义的数组时，为什么它需要一个标准整数？此外，我认为在主程序第 15 行的声明部分我遇到了麻烦，因为 :=get_line 已经被 "Title" 占用。你会如何解决这个问题，有人吗？
也许代码中的错误比这更多，我感谢所有建设性的输入！
我的 .ads 文件
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
package Exercise_BlueBook is
subtype Break_Points is integer range 1..20;
type Breaking_Array is array (1..4) of Break_Points;
type Book_Type is private;
procedure Get (Item: out Book_Type;
Title: in String;
Author: in String;
Width: in Integer;
Height: in Integer;
Break_Points: in Breaking_Array);
procedure Put (Item: in Book_Type);
private
type Book_Type is
record
Title : String(1..100);
Title_L : Integer;
Author : String(1..50);
Author_L : Integer;
Width : Integer;
Height : Integer;
Break_Points : Integer;
end record;
end Exercise_BlueBook;
我的包体adb文件
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
with Exercise_Bluebook; use Exercise_Bluebook;
package body Exercise_BlueBook is
procedure Get (Item: out Book_Type;
Title: in String;
Author: in String;
Width: in Integer;
Height: in Integer;
Break_Points: in Breaking_Array) is
begin
Item.Title_L := Integer'Min (Item.Title'Length, Title'Length);
Item.Title (1..Item.Title_L) := Title(Title'First .. Item.Title_L);
Item.Author_L := Integer'Min (Item.Author'Length, Author'Length);
Item.Author (1..Item.Author_L) := Author (Author'First .. Item.Author_L);
Item.Width := Width;
Item.Height := Height;
Item.Break_Points := Break_Points;
end Get;
procedure Put (Item: in Book_Type) is
begin
Put_Line(Item.Title(1..Item.Title_L));
Put_Line(Item.Author(1..Item.Author_L));
for H in 1..Item.Height loop
Put("!");
for I in 1..Item.Width loop
Put("-");
if I = Breaking_Array(1) then
Put("!");
elsif I = Breaking_Array(2) then
Put("!");
elsif I = Breaking_Array(3) then
Put("!");
elsif I = Breaking_Array(4) then
Put("!");
end if;
end loop;
Put_Line("!");
end loop;
end Put;
end Exercise_BlueBook;
我的主要程序
with ada.text_IO; use ada.text_IO;
with ada.integer_text_IO; use ada.integer_text_IO;
with Exercise_Bluebook; use Exercise_Bluebook;
procedure Exercise_BlueBook_Main is
B : Book_Type;
begin
Put("Enter the name of the book: ");
declare
Title : constant String := Get_Line; -- First Get_Line already taken
Author: constant String := Get_Line; -- How do I solve this for "Author"?
Width: Integer;
Height: Integer;
Break_Points : Exercise_BlueBook.Breaking_Array;
begin
Put("Enter the book's width: ");
Get(Width);
Put("Enter the book's height: ");
Get(Height);
Put("Enter the breaking points for the fold: ");
Get(Break_Points); -- Won't read this as an array?
Get(B,
Title => Title,
Author => Author,
Width => Width,
Height => Height,
Break_Points => Break_Points);
end;
New_Line;
Put(B);
end Exercise_BlueBook_Main;
Ada.Integer_Text_IO 包中的 Get 子程序将只读取一个整数。您可以通过添加循环来扩展它：
main.adb
with Ada.Text_IO; use Ada.Text_IO;
procedure Main is
generic
type Num is range <>;
type Arr is array (Integer range <>) of Num;
procedure Get (From : String; Item : out Arr);
---------
-- Get --
---------
procedure Get (From : String; Item : out Arr) is
package Num_IO is
new Ada.Text_IO.Integer_IO (Num);
Last : Integer := From'First - 1;
begin
for Idx in Item'Range loop
Num_IO.Get (From (Last + 1 .. From'Last), Item (Idx), Last);
end loop;
end Get;
subtype Break_Points is Integer range 1 .. 20;
type Breaking_Array is array (Integer range <>) of Break_Points;
procedure Get_Breaking_Array is
new Get (Break_Points, Breaking_Array);
BA : Breaking_Array (1 .. 4);
begin
Get_Breaking_Array (Get_Line, BA);
New_Line;
Put_Line("Result:");
for BP of BA loop
Put (BP'Image);
New_Line;
end loop;
exception
when Data_Error =>
Put_Line ("Error: Invalid data.");
when End_Error =>
Put_Line ("Error: Not enough elements.");
end Main;
输出（元素太多，只读取前4个）。
$ ./main
1 2 3 4 5 6
Result:
1
2
3
4
输出（元素太少）。
$ ./main
1 2 3
Error: Not enough elements.
输出（非数字数据）。
$ ./main
1 2 x 4
Error: Invalid data.
输出（元素值超出范围）。
$ ./main
1 2 3 100
Error: Invalid data.
就目前而言，主程序提示输入标题，然后为 Title 调用 Get_Line，然后为 Author 调用另一个 Get_Line。下面的数据是使用Gets读取的；工作的方式是读取字符，跳过白色 space 直到找到可能是数字一部分的内容，然后读取更多字符直到找到不能成为数字一部分的内容。
我们一直在推荐表格的原因
declare
Title : constant String := Get_Line;
是一个String是一个fixed-length字符数组；你怎么能提前知道要多长时间呢？其工作方式是所需的实际长度在 运行 时间由 Get_Line.
您可以通过更改提示来解决缺少作者提示的问题："Enter the book’s name and the author’s name, hit RET after each:".
或者您可以嵌套它们：
Put("Enter the name of the book: ");
declare
Title : constant String := Get_Line;
begin
Put("Enter the author's name: ");
declare
Author: constant String := Get_Line;
Width: Integer;
Height: Integer;
Break_Points : Exercise_BlueBook.Breaking_Array;
begin
Put("Enter the book's width: ");
Get(Width);
Put("Enter the book's height: ");
Get(Height);
Put("Enter the breaking points for the fold: ");
现在我们来看看Break_Points。您需要用自己的 Get:
for J in Break_Points'Range loop
Get(Break_Points(J));
end loop;
Get(B,
Title => Title,
Author => Author,
Width => Width,
Height => Height,
Break_Points => Break_Points);
end;
end;