While loop doesn't exit when eof is detected - while-loop

Question

I'm having troubles with the eof sequence at the while loop. Basically I have to read a txt file (sequence) and each character has a different character that will be printed on an exit.txt file. But my while loop doesn't recognize the eof. Here's my code.
program LaboratorioPascal;
uses crt;
var
sec, sal: Textfile;
v: char;
por_especial, cont_palabra, cont_caracter, cont_especial: integer;
vocales2: set of char;
pares: set of char;
impares: set of char;
consonantes: set of char;
consonantes2: set of char;
procedure numeros(var x: char);
begin
case x of
'0': Write(sal, '0');
'1': Write(sal, '1');
'2': Write(sal, '4');
'3': begin
Write(sal, '2');
Write(sal, '7');
end;
'4': Write(sal, '8');
'5': begin
Write(sal, '1');
Write(sal, '2');
Write(sal, '5');
end;
'6': begin
Write(sal, '1');
Write(sal, '2');
end;
'7': begin
Write(sal, '3');
Write(sal, '4');
Write(sal, '3');
end;
'8': begin
Write(sal, '1');
Write(sal, '6');
end;
'9': begin
Write(sal, '7');
Write(sal, '2');
Write(sal, '9');
end;
else Exit;
end;
end;
function vocales(var s: char): char;
begin
case s of
'e': vocales := 'u';
'a': vocales := 'o';
'i': vocales := 'a';
'o': vocales := 'e';
else vocales := 'i';
end;
end;
begin
assign(sec, 'input.txt'); // Le asignamos un archivo del cual lea
reset(sec); // arrancamos la secuencia
read(sec, v); // leemos la secuencia. avz(sec, v)
assign(sal, 'salida.txt');
rewrite(sal);
vocales2 := ['a', 'e', 'i', 'o', 'u'];
pares := ['0', '2', '4', '6', '8'];
impares := ['1', '3', '5', '7', '9'];
consonantes := ['b', 'c', 'd', 'f', 'g', 'h', 'j','k','l','m', 'n'];
consonantes2 := ['p', 'q', 'r', 's', 't', 'v', 'w', 'x', 'y', 'z'];
por_especial := 0;
cont_palabra := 0;
cont_caracter := 0;
cont_especial := 0;
writeln('El objetivo de este programa es cifrar un mensaje para favorecer a la inteligencia Rusa.');
while not eof(sec) do
begin
while v = ' ' do
begin
write(sal, ' ');
read(sec, v);
end;
cont_palabra := cont_palabra + 1;
while v <> ' ' do
begin
if (v in consonantes) or (v in consonantes2) then
begin
write(sal, '1');
end
else
begin
if v in vocales2 then
begin
Write(sal, vocales(v));
end
else
begin
if v in pares then;
begin
numeros(v);
end;
begin
if v in impares then
begin
numeros(v);
end
else
begin
cont_especial := cont_especial + 1;
Write(sal, '#');
end;
end;
end;
end;
read(sec, v);
end;
end;
write(cont_palabra, ' se crifraon con [Exito]');
close(sec);
close(sal);
end.
But the result I have in the exit file (salida.txt) is
1o1ao i1o 1u1 i1 1e1111ie 1iu 1u 1e1ae o i1o 11a11u1o### 1a1########################################################################################################################################################################################################
I've done my research about the eof topic, but I can't find anything about pascal. And if I try to put an
if eof then
Exit;
end;
inside the while loop, and it just read one character from the input.txt file.

Answer 1

The problem is that you are in the inner loop ("while v <> ' ' do") when you come to the end of your input file.
If the last character in the input file is a space, you jump out of the inner loop and out of the outer loop, because you reached eof.
But if it isn't, you stay in the inner loop, and keep reading beyond the eof, until you encounter a space or a problem.
You can change the inner loop's
"while v <> ' ' do"
to
"while (v <> ' ') and (not eof(sec)) do".
Or make it one loop and handle the space in an if statement.