引发CONSTRAINT_ERROR:josephus.adb:50索引检查失败

Question

我正试图运行这段代码，但这行出现了问题：

Soldiers (Number_Of_Soldiers) := Soldier_Type'(Name=>new String'(Line(1..Length)), Alive=>True);

有人能帮我吗？

非常感谢！

--Josephus Problem
with Ada.Text_IO,Ada.Integer_Text_IO;
use Ada;
procedure Josephus is
    type String_Pointer is access String;
    type Soldier_Type is record
       Name  : String_Pointer;
       Alive : Boolean;
    end record;
    Max_Number_Of_Soldiers: constant := 10;
    Number_Of_Soldiers    : Integer range 0..Max_Number_Of_Soldiers := 0;
    -- start with 0 to facilitate modular arithmetic
    Soldiers: array (0..Max_Number_Of_Soldiers-1) of Soldier_Type;
    procedure Next (Index: in out Integer; Interval: Positive) is
    begin
       for I in 1..Interval loop
          loop
            Index := (Index + 1) mod Number_Of_Soldiers;
            exit when Soldiers(Index).Alive;
          end loop;
       end loop;
    end Next;
    Interval : Integer;
    Man      : Integer := Soldiers'First;
begin
     -- get interval from the standard input
     Integer_Text_IO.Get (Interval);
     Text_IO.Skip_Line;
     Text_IO.Put ("Skip every ");
     Integer_Text_IO.Put (Interval, Width=>1);
     Text_IO.Put_Line (" soldiers.");
     -- get names (one per line) from the standard input
    declare
        Line: String (1..10);
        Length: Integer;

    begin
       while not (Text_IO.End_Of_File) loop
          Text_IO.Get_Line (Line, Length);
      Soldiers (Number_Of_Soldiers) := Soldier_Type'(Name=>new String'(Line(1..Length)), Alive=>True);
          Number_Of_Soldiers := Number_Of_Soldiers + 1;
       end loop;
    end;

    for I in 1..Number_Of_Soldiers-1 loop
        Soldiers(Man).Alive := False;
        Text_IO.Put (Soldiers(Man).Name.all);
        Text_IO.Put_Line (" commits suicide.");
        Next (Man, Interval);
    end loop;
     Text_IO.Put (Soldiers(Man).Name.all);
     Text_IO.Put_Line (" is the last.");
end Josephus;

Answer 1

我认为您的问题是线路

Max_Number_Of_Soldiers: constant := 10;

显然，指定的数字需要大于输入中的最大可能条目数！

无界输入数据集的问题是考虑使用Ada.Containers.Vectors而不是数组的原因之一。