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%!PS-Adobe-3.0
%%Pages: 1
%%EndComments
%
% Task #2: "Is the room open?
%
% There are 500 rooms in a hotel with 500 employees having keys to all the
% rooms. The first employee opened main entrance door of all the rooms. The
% second employee then closed the doors of room numbers 2,4,6,8,10 and
% so on to 500. The third employee then closed the door if it was opened
% or opened the door if it was closed of rooms 3,6,9,12,15 and so on to
% 500. Similarly the fourth employee did the same as the third but only
% room numbers 4,8,12,16 and so on to 500. This goes on until all employees
% has had a turn.
%
% Write a script to find out all the rooms still open at the end.
% "
%
% Debugging....
% const debuglm: left margin of debug messages
/debuglm 0.5 72 mul def
% const debugtop: top of debug messages - 11 inches up.
/debugtop 11 72 mul def
% const debugdown: how far to go down each line
/debugdown 20 def
% debugorigin():
% move to debugging origin
/debugorigin
{
debuglm debugtop moveto
(Debugging log:) show
newline
} bind def
% debugnv( name, value );
% display name and value on a debug line.
% keep this as it's so much simpler than debug() below
% and also debug() has commented out invocations to
% this throughout it:-)
/debugnv
{
% initially: stack top: value, name
30 0 rmoveto
exch % stack top: name, value
show % show name, stack top: value
(: ) show
80 string cvs show % show convert_to_string(value)
newline
} bind def
% debugsay( string, array_of_pairs );
% display a single message, combining the initial string and then
% every pair of items (variable,string) in <array> with no separators.
% eg debugsay( (x:), [ x (, y:) y (, z:) z ()] ) produces
% "x: value_of_x, y: value_of_y, z: value_of_z"
/debugsay
{
6 dict begin % next N items defined are in a local dictionary
/array exch def % localize parameter name, removing it from stack
/initstr exch def % localize parameter name, removing it from stack
/len 0 def % local variable - length of array
/pos 0 def % local variable - position in array
/name () def % local variable - an array element
/value () def % local variable - next array element
30 0 rmoveto
/len array length def
initstr 80 string cvs show
% for pos = 0 to $#array step 2
0 2 len 1 sub
{
/pos exch def
% (pos) pos debugnv
% $name = $array[$pos];
/name array pos get def
% (name) name debugnv
% $value = $array[$pos+1];
/value array pos 1 add get def
% (value) value debugnv
name 80 string cvs show
value 80 string cvs show
} for
newline
end % local dictionary destroyed here
} def
% newline();
% go to left margin of next line for debug messages
/newline
{
currentpoint debugdown sub % decrement Y pos
exch pop % drop old X
debuglm exch % form (debuglm,Y) on stack
moveto % go there!
} def
% str = i2s(n):
% convert n to a string
/i2s
{
20 string cvs
} def
% result = append( string1, string2 )
% Concatenates two strings together. Some languages
% already know how to do stuff like this!!!
/append
{
% Initial stack: s1 s2 <-- top of stack
2 copy % s1 s2 s1 s2
length % s1 s2 s1 len(s2)
exch % s1 s2 len(s2) s1
length add % s1 s2 len(s1)+len(s2)
string dup % s1 s2 r r
4 2 roll % r r s1 s2
2 index % r r s1 s2 r
0 % r r s1 s2 r 0
3 index % r r s1 s2 r 0 s1
putinterval % strcpy( r+0, s1 )
% r r s1 s2
exch % r r s2 s1
length % r r s2 len(s1)
exch % r r len(s1) s2
putinterval % strcpy( r+len(s1), s2 )
% return r
} bind def
%%Page: 1 1
%%PageOrientation: Portrait
/Helvetica-Bold findfont 13 scalefont setfont
debugorigin
% n = 500
/n 500 def
% say "answer:"
(answer:) [] debugsay
% for r = 1 to n
1 1 n
{
/r exch def
% odd=1
/odd 1 def
% for i = 2 to r
2 1 r
{
/i exch def
% if r % i == 0?
r i mod 0 eq
{
% odd = 1-odd
/odd 1 odd sub def
} if
} for
% if odd
odd 1 eq
{
% say "$r"
() [r ()] debugsay
} if
} for
showpage
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