Reading a text file

Reading a text file

[stiletto]

Hello All!

How can I read text file?  Following program is supposed to read a text 
file and print out the contents of the file, but I got following error 
messages.

Thanks in advance

test.adb:13:01: "Read" is not visible
test.adb:13:01: non-visible (private) declaration at a-textio.ads:348
test.adb:13:01: non-visible declaration at a-stream.ads:58
gnatmake: "test.adb" compilation error


with Ada.Text_IO;
use Ada.Text_IO;

procedure test is
Data_File : File_Type;
Result_File : File_Type;
St : String(1..100);
begin

Open(Data_File, In_File, "infile");

while not End_Of_File(Data_File) loop
  Read(Data_File, St);
  Put_Line(St);
end loop;

end test;

Re: Reading a text file

[DPH]

Note that the procedure "Read" is not a part of Ada.Text_IO.  That is why
it is not visible.  You probably want the procedure "Get" which is in
Ada.Text_IO.  All the details are in A.10.1 of the Ada 95 Reference Manual.

Dave Head

stiletto@ryuji.net wrote:

> Hello All!
>
> How can I read text file?  Following program is supposed to read a text
> file and print out the contents of the file, but I got following error
> messages.
>
> Thanks in advance
>
> test.adb:13:01: "Read" is not visible
> test.adb:13:01: non-visible (private) declaration at a-textio.ads:348
> test.adb:13:01: non-visible declaration at a-stream.ads:58
> gnatmake: "test.adb" compilation error
>
> with Ada.Text_IO;
> use Ada.Text_IO;
>
> procedure test is
> Data_File : File_Type;
> Result_File : File_Type;
> St : String(1..100);
> begin
>
> Open(Data_File, In_File, "infile");
>
> while not End_Of_File(Data_File) loop
>   Read(Data_File, St);
>   Put_Line(St);
> end loop;
>
> end test;

Re: Reading a text file

[DPH]

Note that the procedure "Read" is not a part of Ada.Text_IO.  That is why
it is not visible.  You probably want the procedure "Get" which is in
Ada.Text_IO.

Dave Head

stiletto@ryuji.net wrote:

> Hello All!
>
> How can I read text file?  Following program is supposed to read a text
> file and print out the contents of the file, but I got following error
> messages.
>
> Thanks in advance
>
> test.adb:13:01: "Read" is not visible
> test.adb:13:01: non-visible (private) declaration at a-textio.ads:348
> test.adb:13:01: non-visible declaration at a-stream.ads:58
> gnatmake: "test.adb" compilation error
>
> with Ada.Text_IO;
> use Ada.Text_IO;
>
> procedure test is
> Data_File : File_Type;
> Result_File : File_Type;
> St : String(1..100);
> begin
>
> Open(Data_File, In_File, "infile");
>
> while not End_Of_File(Data_File) loop
>   Read(Data_File, St);
>   Put_Line(St);
> end loop;
>
> end test;

Reading a text file

[stiletto]

Hello All!

How can I read text file?  Following program is supposed to read a text 
file and print out the contents of the file, but I got following error 
messages.

Thanks in advance

test.adb:13:01: "Read" is not visible
test.adb:13:01: non-visible (private) declaration at a-textio.ads:348
test.adb:13:01: non-visible declaration at a-stream.ads:58
gnatmake: "test.adb" compilation error


with Ada.Text_IO;
use Ada.Text_IO;

procedure test is
Data_File : File_Type;
Result_File : File_Type;
St : String(1..100);
begin

Open(Data_File, In_File, "infile");

while not End_Of_File(Data_File) loop
  Read(Data_File, St);
  Put_Line(St);
end loop;

end test;

Re: Reading a text file

[Mathias Dolidon]

stiletto@ryuji.net a �crit :
> 
> Hello All!
> 
> How can I read text file?  Following program is supposed to read a text
> file and print out the contents of the file, but I got following error
> messages.
> 
> Thanks in advance
> 
> test.adb:13:01: "Read" is not visible
> test.adb:13:01: non-visible (private) declaration at a-textio.ads:348
> test.adb:13:01: non-visible declaration at a-stream.ads:58
> gnatmake: "test.adb" compilation error
> 
> with Ada.Text_IO;
> use Ada.Text_IO;
> 
> procedure test is
> Data_File : File_Type;
> Result_File : File_Type;
> St : String(1..100);
> begin
> 
> Open(Data_File, In_File, "infile");
> 
> while not End_Of_File(Data_File) loop
>   Read(Data_File, St);
>   Put_Line(St);
> end loop;
> 
> end test;

Instead of "Read(Data_File, St)" write "Get_Line(Data_File, St)".

There's also another way to detecte the EOF :

--------
begin
loop
Get_Line(Data_File, St);
Put_Line(St);
end loop;

exception
  when end_error => close(Data_File);
end;
----------

Bye,
Mathias

-- 
http://www.mdlabs.ovh.org

Re: Reading a text file

[Marin David Condic]

Mathias Dolidon wrote:

> Instead of "Read(Data_File, St)" write "Get_Line(Data_File, St)".
>

From the ARM 10.1(49)

49.   procedure Get_Line(File : in  File_Type;
                           Item : out String;
                           Last : out Natural);

You've got the right idea, but you will need a "Last" actual parameter, which
indicates the last character in the string.

BTW, while the exception trap will, in fact, work for detecting EOF, I'd
consider it a bit abnormal. EOF is a condition you expect to arrive at sort
of like getting to the end of an array with an index. Most people would not
terminate an array scanning loop by trapping Constraint_Error, even though
it would work. Exceptions are generally considered an indication of some
unexpected condition or error. You would not usually use them for "normal"
program conditions.

MDC
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