Here's the source can you find the mistake?

var i,sum1,n:longint;
begin
   readln(n);
   sum1:=0;
   if n=1 then sum1:=2
   else
     if n<=0 then
      for i:=1 downto n do sum1:=sum1+i;
     else
      for i:=1 to n do sum1:=sum1+i;
   writeln(sum1);
end.

> you had to check it!!! it has stupid error:
> before "else" - no ";"!!!!!

when n = 1, the sum is 1 (not 2 like in your output)

btw, you have a formula for this problems, that is, the sum
of all interger numbers lying between N1 and N2 (N1 <= N2)
is

(N1 + N2) * (N2 - N1 + 1) / 2

Good luck !

DQH (DSAP Group)
Mg9h@yahoo.com
http://dsapvn.hypermart.net


> Here's the source can you find the mistake?
>
> var i,sum1,n:longint;
> begin
>    readln(n);
>    sum1:=0;
>    if n=1 then sum1:=2
>    else
>      if n<=0 then
>       for i:=1 downto n do sum1:=sum1+i;
>      else
>       for i:=1 to n do sum1:=sum1+i;
>    writeln(sum1);
> end.
>
>

when n = 1, the sum is 1 (not 2 like in your output)

btw, you have a formula for this problems, that is, the sum
of all interger numbers lying between N1 and N2 (N1 <= N2)
is

(N1 + N2) * (N2 - N1 + 1) / 2

Good luck !

DQH (DSAP Group)
Mg9h@yahoo.com
http://dsapvn.hypermart.net


> Here's the source can you find the mistake?
>
> var i,sum1,n:longint;
> begin
>    readln(n);
>    sum1:=0;
>    if n=1 then sum1:=2
>    else
>      if n<=0 then
>       for i:=1 downto n do sum1:=sum1+i;
>      else
>       for i:=1 to n do sum1:=sum1+i;
>    writeln(sum1);
> end.
>
>

Hei, I've tried this formula, look at my source :
var
 i : integer;
 h : longint;
begin
readln(i);
h := i + 1;
h := h * i;
writeln((h/2):0:0);
end.

but i still got wrong answer, what's wrong. and btw, is
that's the formula, i think the example is wrong.
thanx


> when n = 1, the sum is 1 (not 2 like in your output)
>
> btw, you have a formula for this problems, that is, the
sum
> of all interger numbers lying between N1 and N2 (N1 <=
N2)
> is
>
> (N1 + N2) * (N2 - N1 + 1) / 2
>
> Good luck !
>
> DQH (DSAP Group)
> Mg9h@yahoo.com
> http://dsapvn.hypermart.net
>
>
> > Here's the source can you find the mistake?
> >
> > var i,sum1,n:longint;
> > begin
> >    readln(n);
> >    sum1:=0;
> >    if n=1 then sum1:=2
> >    else
> >      if n<=0 then
> >       for i:=1 downto n do sum1:=sum1+i;
> >      else
> >       for i:=1 to n do sum1:=sum1+i;
> >    writeln(sum1);
> > end.
> >
> >

No, the wrong things belong to you, the example is
absolutely right!
1. 'bout the example, n = -3, that the sequence is
    -3 -2 -1 0 1
    and the sum counted by
    (-3) + (-2) + (-1) + 0 + 1 = -5
    Is it right ?
2. Your prog is wrong, with my formula, you have to count
   the sum from input (in your prog is the variable i) to 1,
   that means the source must be something like this

   input i
   if i < 1 then sum = (( 1 + i) * ( 2 - i)) div 2;
   if i >=1 then sum = (( i + 1) * i) div 2;
   output sum
3. Don't use /2 if not nesscessary, just use div 2 for the
   correction.

Good luck !
QH@
> Hei, I've tried this formula, look at my source :
> var
>  i : integer;
>  h : longint;
> begin
> readln(i);
> h := i + 1;
> h := h * i;
> writeln((h/2):0:0);
> end.
>
> but i still got wrong answer, what's wrong. and btw, is
> that's the formula, i think the example is wrong.
> thanx
>
>
> > when n = 1, the sum is 1 (not 2 like in your output)
> >
> > btw, you have a formula for this problems, that is, the
> sum
> > of all interger numbers lying between N1 and N2 (N1 <=
> N2)
> > is
> >
> > (N1 + N2) * (N2 - N1 + 1) / 2
> >
> > Good luck !
> >
> > DQH (DSAP Group)
> > Mg9h@yahoo.com
> > http://dsapvn.hypermart.net
> >
> >
> > > Here's the source can you find the mistake?
> > >
> > > var i,sum1,n:longint;
> > > begin
> > >    readln(n);
> > >    sum1:=0;
> > >    if n=1 then sum1:=2
> > >    else
> > >      if n<=0 then
> > >       for i:=1 downto n do sum1:=sum1+i;
> > >      else
> > >       for i:=1 to n do sum1:=sum1+i;
> > >    writeln(sum1);
> > > end.
> > >
> > >

> > Here's the source can you find the mistake?
> >
> > var i,sum1,n:longint;
> > begin
> >    readln(n);
> >    sum1:=0;
> >    if n=1 then sum1:=2
> >    else
> >      if n<=0 then------------------>this is the
mistakes ( n<=1 )
> >       for i:=1 downto n do sum1:=sum1+i;
> >      else
> >       for i:=1 to n do sum1:=sum1+i;
> >    writeln(sum1);
> > end.
> >
> >

i don know why u use so such prog that run in O(n) my prog run
in O(1);
my mail is ioi_khafan@hotmail.com
here it is :
var
   n    : longint;
begin
  read (n);
  if  n = 0 then
      begin
           writeln ('1');
           exit;
      end
  else
  if n > 0 then
     n := ( n * (n + 1) ) div 2
  else
      begin
           n := -1 * n;
           n := ( n * (n + 1) ) div 2;
           n := n - 1;
           n := -1 * n;
      end;
  writeln (n);
end.

var
   n,k:integer;
   sum:longint;
begin
readln(n);
if n<0 then
begin for k:=n to 1 do
 sum:=sum+k; end
   else  if n>0 then begin for k:=1 to n do
     sum:=sum+k;
end;
write(sum);
end.
salam
men demek isteyirem ki bur daki sehv why