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(*
* TASK #2 - Summations
*
* GUEST LANGUAGE: THIS IS THE C VERSION OF ch-2.pl, suitable for
* the Free Pascal compiler.
*)
uses sysutils;
const maxints = 256;
type intarray = array [0..maxints-1] of integer;
var debug : boolean;
(* process_args( nel, v );
* Process command line arguments,
* specifically process the -d flag,
* set nel to the number of remaining arguments,
* check that all those remaining arguments are +ve numbers,
* copy remaining args to a new integer array v.
*)
procedure process_args( var nel : integer; var v : intarray );
(* note: paramStr(i)); for i in 1 to paramCount() *)
var
nparams : integer;
arg : integer;
i : integer;
p : string;
begin
nparams := paramCount();
arg := 1;
if (nparams>0) and SameText( paramStr(arg), '-d' ) then
begin
debug := true;
arg := 2;
end;
nel := 1+nparams-arg;
if nel < 2 then
begin
writeln( stderr,
'Usage: summations [-d] list of +ve numbers' );
halt;
end;
if nel > maxints then
begin
writeln( stderr,
'summations too many numbers (max ',
maxints, ')' );
halt;
end;
if debug then
begin
writeln( 'debug: arg', arg, ', nparams=', nparams, ', nel=',
nel );
end;
// elements are in argv[arg..nparams], copy them to v[]
// check that all remaining arguments are +ve integers,
// and then copy them to v[]
for i := arg to nparams do
begin
p := paramStr(i);
if (p[1] < '0') or (p[1] > '9') then
begin
writeln( stderr,
'summations arg ', i,
' (', p, ') is not a +ve number' );
halt;
end;
v[i-arg] := StrToInt( p );
end;
end;
procedure main;
var
nel : integer;
v : intarray;
r, i : integer;
pos : integer;
begin
debug := false;
process_args( nel, v );
r := 1;
if debug then
begin
write( 'row ', r, ':' );
for i := 0 to nel-1 do
begin
write( ' ', v[i] );
end;
writeln;
end;
while nel > 1 do
begin
// shift v array down
for i := 0 to nel-1 do
begin
v[i] := v[i+1];
end;
v[nel-1] := -1;
nel := nel - 1;
for pos := 1 to nel-1 do
begin
v[pos] += v[pos-1];
end;
r := r+1;
if debug then
begin
write( 'row ', r, ':' );
for i := 0 to nel-1 do
begin
write( ' ', v[i] );
end;
writeln;
end;
end;
writeln( v[0] );
end;
begin
main;
end.
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