ADA

Question

我是编程新手，这是我第一次尝试使用记录数据容器。我在打印第 65-70 行之间的哈希图时遇到困难。我猜我需要分解记录并单独打印它的每个属性，但我不确定最好的方法。错误状态“没有候选者与实际匹配：缺少参数参数。

with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
with Ada.Text_IO.Unbounded_IO; use Ada.Text_IO.Unbounded_IO;
with Ada.Strings.Hash;
with Ada.Containers.Hashed_Maps;
with Ada.Characters.Handling;

procedure Hashmap_Records is


   type Guest is record
      Name : Unbounded_String := Null_Unbounded_String;
      Attending : Boolean := False;
      Vegitarian : Boolean := False;
      Kids : Natural := 0;
   end record;

   function Equivalent_Keys(Left : Unbounded_String;
                            Right : Unbounded_String)
                            return Boolean is
   begin
      return Left = Right;
      end Equivalent_Keys;

   function U_To_L(Key : in Unbounded_String)
                   return Unbounded_String is
   begin
      return To_Unbounded_String(Ada.Characters.Handling.To_Lower(To_String(Key)));
   end U_To_L;

   function Hash_Func(Key : in Unbounded_String)
                      return Ada.Containers.Hash_Type is
   begin
      return Ada.Strings.Hash(To_String(Key));
   end Hash_Func;


   package Guest_Tracker is new Ada.Containers.Hashed_Maps(Key_Type => Unbounded_String,
                                                           Element_Type => Guest,
                                                           Hash => Hash_Func,
                                                           Equivalent_Keys => Equivalent_Keys);
   Tracked_Guests : Guest_Tracker.Map;

   User_Input : Natural := 0;

   Name_Input : Unbounded_String := Null_Unbounded_String;
   Name : Unbounded_String := Null_Unbounded_String;
   Attendance_Input : Unbounded_String := Null_Unbounded_String;
   Vegitarian_Input : Unbounded_String := Null_Unbounded_String;
   Kids_Input : Natural := 0;
   Temp_Attendance : Boolean := False;
   Temp_Vegi : Boolean := False;


   Procedure Populate_Hash_Map is
   begin
      Tracked_Guests.Insert(Key => To_Unbounded_String("John Smith"),
                            New_Item => (To_Unbounded_String("John"), True, False, 1));
      Tracked_Guests.Insert(Key => To_Unbounded_String("Robert Johnson"),
                           New_Item => (To_Unbounded_String("Rob"), True, True, 2));

   end Populate_Hash_Map;

   procedure Print_Hash_Map(Position : Guest_Tracker.Cursor) is                ---
   begin
      Put_Line("The key: " & To_String(Guest_Tracker.Key(Position)) &
                 " the data item: ");
      Put(Guest_Tracker.Element(Position));                                    ----THIS IS WHERE ERRORS OCCUR
   end Print_Hash_Map;                                                          ----


begin
   Populate_Hash_Map;
   loop
      Put_Line(" - Menu - ");
      Put_Line(" - 1 - Enter new value.");
      Put_Line(" - 2 - Delete Existing Value.");
      Put_Line(" - 3 - Print entire hashmap.");
      Put_Line(" - 4 - Exit Application.");
      New_Line;
      Put(" - > ");

      declare
      begin
         Get(User_Input);
      exception
         when Data_Error =>
            Put_Line("ERROR : The entered value is not an integer, please try again!");
            User_Input := 0;
         when others =>
            Put_Line("ERROR: An unknown error has occured!");
      end;

      Skip_Line;
      New_Line;

      if User_Input = 1 then
         Put_Line("Enter a new value.");
         Put(" Name - > ");
         Name_Input := Get_Line;
         Name := Name_Input;
         New_Line;

         Put(" Attending? (yes/y/no/n) - > ");
         Attendance_Input := Get_Line;
         New_Line;

         Put(" Vegitarian? (yes/y/no/n) - > ");
         Vegitarian_Input := Get_Line;
         New_Line;

         Put("How many children attending? - > ");
         Get(Kids_Input);
         New_Line;

         if (U_To_L(Attendance_Input) = To_Unbounded_String("no"))
           or (U_To_L(Attendance_Input) = To_Unbounded_String("n")) then
            Temp_Attendance := False;

         elsif (U_To_L(Attendance_Input) = To_Unbounded_String("y"))
           or (U_To_L(Attendance_Input) = To_Unbounded_String("yes")) then
            Temp_attendance := True;

         else
            Put_Line("WARNING: The confirmation that you entered is not recognized.");
         end if;

         if (U_To_L(Vegitarian_Input) = To_Unbounded_String("no"))
           or (U_To_L(Vegitarian_Input) = To_Unbounded_String("n")) then
            Temp_Vegi := False;

         elsif (U_To_L(Vegitarian_Input) = To_Unbounded_String("y"))
           or (U_To_L(Vegitarian_Input) = To_Unbounded_String("yes")) then
            Temp_Vegi := True;

         else
            Put_Line("WARNING: The confirmation that you entered is not recognized.");
         end if;

         Guest_Tracker.Insert(Container => Tracked_Guests,
                                 Key => Name_Input,
                                 New_item => (Name, Temp_Attendance, Temp_Vegi, Kids_Input));



      elsif User_Input = 2 then
         Put("Delete a value - > ");
         Name_Input := Get_Line;
         New_Line;

         declare
         begin
            Guest_Tracker.Delete(Container => Tracked_Guests,
                                      Key => Name_Input);
         exception
            when Constraint_Error =>
               Put_Line("The name: '" & To_String(Name_Input) & "' is not found.");
            when others =>
               Put_Line("ERROR: Another error has been discovered!");
         end;
      elsif User_Input = 3 then
         Tracked_Guests.Iterate(Print_Hash_Map'access);
         New_Line;
      elsif User_Input = 4 then
         exit;
      end if;
   end loop;

   end Hashmap_Records;

Answer 1

这与哈希映射无关。您假设有一个 Put 过程输出您的记录类型 Guest 但实际上有 none。您只有来自 Ada.Text_IO、Ada.Integer_Text_IO 和 Ada.Text_IO.Unbounded_IO 的 Put 子例程可用，其中 none 以 Guest 类型的值作为参数。

当您定义记录类型时，Ada 不会自动生成一个子程序来漂亮地打印记录值。你必须自己做，例如

procedure Put (Value : Guest) is
begin
   Put ("Guest(Name: ");       --  supplied by Ada.Text_IO
   Put (Value.Name);           --  supplied by Ada.Text_IO.Unbounded_IO
   Put (", Attending: ");
   Put (Value.Attending'Img);  --  'Img is GNAT-specific; standard is
                               --  Boolean'Image (Value.Attending)
   Put (", Vegitarian: ");
   Put (Value.Vegitarian'Img);
   Put (", Kids: ");
   Put (Value.Kids);           --  supplied by Ada.Integer_Text_IO
   Put (")");
end Put;

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