[SOLVED]Program experiencing runtime error, not displaying expected output.

[Cainnech]

Hello, guys.
I am using the latest free pascal compiler and I am on windows 11.
 
I recently got my hands on an old pascal textbook, and I have been trying to learn from it since I have no experience with pascal and my programming skills and problem solving skills aren't great at all (they are really bad), so I wanted to go back to basics to build up a solid foundation this time.

I have encountered a problem trying to replicate one of the examples, the other examples work well but this one doesn't. It compiles but when I try to insert data, it doesn't output anything.

It's supposed to work like this:
INPUT: baa, baa, black sheep.
OUTPUT: 16 Characters, 3 blanks, 2 commas, 1 period

This is the program:

Code: Pascal  [Select][+][-]

1.  program countchars(input, output);
2. {$MODE ISO}
3.   const
4.     blank = ' ';
5.     comma = ',';
6.     period = '.';
7.  
8.   var
9.     charcount, blankcount, commacount, periodcount: integer;
10.     character : char;
11.   begin
12.      charcount := 0;
13.      commacount := 0;
14.      blankcount := 0;
15.      periodcount := 0;
16.      while not eof do
17.         begin
18.            read(character);
19.            charcount := charcount + 1;
20.            if character = blank
21.              then blankcount := blankcount + 1
22.            else if character = comma
23.              then commacount := commacount + 1
24.            else if character = period
25.              then periodcount := periodcount + 1
26.         end;
27.     writeln (charcount, 'characters');
28.     writeln (blankcount, 'blanks');
29.     writeln (periodcount, 'periods');
30.     writeln (commacount, 'commas');
31.   end.
32.  
33.  

I am not sure what to do, or what the problem is.

I also encountered another issue, when I tried replacing the "char" type with a "string" type, it returned exit code 201, Apparently this is a range check error and it's trying to store a value where it doesn't fit. I would like to know why, because isn't the string type bigger than the char type, so why does it crash whenever I try storing strings in the string type.

Thank you in advance,
Kenneth.

[Handoko]

@Cainnech

I try to change as little as possible from your code to make it works:

Code: Pascal  [Select][+][-]

1. program countchars(input, output);
2.  
3. uses
4.   Types;
5.  
6. {$MODE ISO}
7.  
8.  
9.   const
10.     blank = ' ';
11.     comma = ',';
12.     period = '.';
13.  
14.   var
15.     charcount, blankcount, commacount, periodcount: integer;
16.     characters : string;
17.     character: char;
18.     i: byte;
19.   begin
20.      charcount := 0;
21.      commacount := 0;
22.      blankcount := 0;
23.      periodcount := 0;
24.      ReadLn(characters);
25.      for i := 0 to Length(characters)-1 do
26.      begin
27.        character := characters[i+1];
28.        charcount := charcount + 1;
29.        if characters[i+1] = blank
30.          then blankcount := blankcount + 1
31.        else if character = comma
32.          then commacount := commacount + 1
33.        else if character = period
34.          then periodcount := periodcount + 1
35.     end;
36.     writeln (charcount, 'characters');
37.     writeln (blankcount, 'blanks');
38.     writeln (periodcount, 'periods');
39.     writeln (commacount, 'commas');
40.   end.

[Cainnech]

Thank you so much, it works perfectly.

[Zvoni]

Thank you so much, it works perfectly.

I disagree.
Handoko's code returns for charcount the length of the String

Code: Pascal  [Select][+][-]

1. program countchars(input, output);
2. uses Types;
3. {$MODE ISO}
4. const
5.     blank = ' ';
6.     comma = ',';
7.     period = '.';
8.  
9.   var
10.     charcount, blankcount, commacount, periodcount: integer;
11.     characters : string;
12.     character: char;
13.     i: byte;
14.   begin
15.     charcount := 0;
16.     commacount := 0;
17.     blankcount := 0;
18.     periodcount := 0;
19.     ReadLn(characters);
20.     for i := 1 to Length(characters) do
21.     begin
22.        Case characters[i] Of
23.          blank : blankcount := blankcount + 1;
24.          comma : commacount := commacount + 1;
25.          period: periodcount := periodcount + 1;
26.        end;
27.     end;
28.     charcount:=Length(characters)-(blankcount+commacount+periodcount);
29.     writeln (charcount, ' characters');
30.     writeln (blankcount, ' blanks');
31.     writeln (periodcount, ' periods');
32.     writeln (commacount, ' commas');
33.     Readln;
34.   end.

[marcov]

If you want to keep it strictly ISO, try replacing EOF with EOLN

[tetrastes]

It's supposed to work like this:
INPUT: baa, baa, black sheep.

INPUT: baa, baa, black sheep.EOF (windows Ctrl+Z, unix usually Ctrl+D)

[Thaddy]

Marcov is right, EOLN is correct. EOF means that input -a.k.a. stdin - reads end of file, which it isn't. EOF depends on programming style. (and dialect)  As long as the file is open (input) EOF is technically wrong. EOF reads beyond line endings.

[tetrastes]

I don't bother if it technically wrong or not, but original program can parse multuline input (and piping of multiline files), what EOLN variant cannot do, of course:

[Thaddy]

That is what I wrote..... It is simply how read and readln works that Marcov is right.