New subject: Standard Pascal (was: packed array bug? or spec?)

15 Aug 2000


      Hi all.
I'm Takashi Yamanoue, in Japan.
  (http://www.tobata.isc.kyutech.ac.jp/~yamanoue)
  (http://www.tobata.isc.kyutech.ac.jp/~yamanoue/researches/complang.html)
The output of the following program seems strange.
  Is it the specification? or a bug?
I've searched the archives of this list, and I've found out a
  similar bug in the Borland Pascal Format, 
  and I've also found out the article which said that it was fixed.
I've updated the gcc and gpc. However, the following phenomenon
  was not fixed.
Thank you in advance.
Takashi, yamanoue@isc.kyutech.ac.jp
-------------------------------------------------------
program exercise28(input, output);
const smax  = 8;
      smax2 = 9;
      n	    = 10;
type str    = packed array[1..smax] of char;
     str2   = packed array[1..smax2] of char;
var i, j: integer;
    s: array[1..n] of str; tmp: str;
    s2: array[1..n] of str2; tmp2: str;
begin
{ the following part uses the 8 chars packed array}
s[1]:='abababab';
   s[2]:='babababa';
   s[3]:='12121212';
   s[4]:='21212121';
   s[5]:='cdcdcdcd';
   s[6]:='dcdcdcdc';
   s[7]:='56565656';
   s[8]:='65656565';
   s[9]:='bcbcbcbc';
   s[10]:='cbcbcbcb';
for i := 1 to n - 1 do
    	for j := n - 1 downto i do
    		if s[j] > s[j + 1] then
    		begin
    			tmp := s[j];
    			s[j] := s[j + 1];
    			s[j + 1] := tmp
    		end;
    for i := 1 to n do
       writeln('s[', i:2, '] = ', s[i]);
{ the following part uses the 9 chars packed array}
s2[1]:='abababab';
   s2[2]:='babababa';
   s2[3]:='12121212';
   s2[4]:='21212121';
   s2[5]:='cdcdcdcd';
   s2[6]:='dcdcdcdc';
   s2[7]:='56565656';
   s2[8]:='65656565';
   s2[9]:='bcbcbcbc';
   s2[10]:='cbcbcbcb';
for i := 1 to n - 1 do
    	for j := n - 1 downto i do
    		if s2[j] > s2[j + 1] then
    		begin
    			tmp := s2[j];
    			s2[j] := s2[j + 1];
    			s2[j + 1] := tmp
    		end;
    for i := 1 to n do
    	writeln('s2[', i:2, '] = ', s2[i])
end.
{
 the following is the output of this program.
yamanoue% gpc gpcbug.pas
   yamanoue% a.out
   s[ 1] = 21212121
   s[ 2] = 12121212
   s[ 3] = 65656565
   s[ 4] = 56565656
   s[ 5] = babababa
   s[ 6] = abababab
   s[ 7] = cbcbcbcb
   s[ 8] = bcbcbcbc
   s[ 9] = dcdcdcdc
   s[10] = cdcdcdcd
   s2[ 1] = 12121212 
   s2[ 2] = 21212121 
   s2[ 3] = 56565656 
   s2[ 4] = 65656565 
   s2[ 5] = abababab 
   s2[ 6] = babababa 
   s2[ 7] = bcbcbcbc 
   s2[ 8] = cbcbcbcb 
   s2[ 9] = cdcdcdcd 
   s2[10] = dcdcdcdc 
   yamanoue% gpc -v
   Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.95.2/specs
   gpc version 20000808, based on 2.95.2 19991024 (release)
   yamanoue%
The desired output is
   s[ 1] = 12121212 
   s[ 2] = 21212121 
   s[ 3] = 56565656 
   s[ 4] = 65656565 
   s[ 5] = abababab 
   s[ 6] = babababa 
   s[ 7] = bcbcbcbc 
   s[ 8] = cbcbcbcb 
   s[ 9] = cdcdcdcd 
   s[10] = dcdcdcdc 
   s2[ 1] = 12121212 
   s2[ 2] = 21212121 
   s2[ 3] = 56565656 
   s2[ 4] = 65656565 
   s2[ 5] = abababab 
   s2[ 6] = babababa 
   s2[ 7] = bcbcbcbc 
   s2[ 8] = cbcbcbcb 
   s2[ 9] = cdcdcdcd 
   s2[10] = dcdcdcdc
}