GENERATING alternate numbers

[rohithverma]

I have a input like below:

  loanno    deb          cred          id

  1234      27199         0             R
  1234      27199         0             R
  1234          0          27199        P
  1234          0          27199        P

  567         2000        0               R

  567         2000         0              R

  567            0          2000          P

I need ouput like 

  loanno    deb          cred          id       flag

  1234      27199         0             R      equal

   1234          0          27199        P     equal
  1234      27199         0             R      equal
  1234          0          27199        P       equal

  567         2000        0               R      equal

   567            0          2000          P      equal

  567         2000         0              R       not equal

  Please help me .......Thanks in advance

[novinosrin]

data have;
input   loanno    deb          cred          id	$;
cards;
  1234      27199         0             R
  1234      27199         0             R
  1234          0          27199        P
  1234          0          27199        P
  567         2000        0               R
  567         2000         0              R
  567            0          2000          P
  ;

data need;
 do _n_=1 by 1 until(last.loanno);
  set have;
  by loanno notsorted;
  length flag $7;
  if first.loanno and not last.loanno then flag='equal';
  else if mod(_n_,2) ne 0 and  last.loanno then flag='Unequal';
  if mod(_n_,2)=0 then do;
   cred=max(deb,cred);
   deb=0;
  end;
  else do;
   deb=max(deb,cred);
   cred=0;
  end;
  output;
 end;
run;

   

[VENKATAMAHESH]

Check this solution...

data original;
input loanno deb cred id$;
lines;
1234 27199 0      R
1234 27199 0      R
1234 0     27199  P
1234 0     27199  P
567  2000  0      R
567  2000  0      R
567  0     2000   P
;
run;

proc sort;
by loanno deb cred id;
run;

data original;
set original;
by loanno;
if first.loanno then seq = 0;
seq+1;
run;

data even odd;
set original;
if mod(seq,2) = 0 then output even;
else output odd;
run;

proc sort data=even;
by descending loanno descending deb cred id;
run;

proc sort data=odd;
by descending loanno descending deb cred id;
run;

data final;
set odd even;
run;

proc sort;
by descending loanno;
run;

data final(drop=seq);
set final END = EOF;
if EOF then flag = "not equal";
else flag = "equal";
run;

[Ksharp]

data have;
input   loanno    deb          cred          id	$;
cards;
  1234      27199         0             R
  1234      27199         0             R
  1234          0          27199        P
  1234          0          27199        P
  567         2000        0               R
  567         2000         0              R
  567            0          2000          P
  ;
data temp;
 set have;
 by loanno id notsorted;
 if first.id then n=0;
 n+1;
run;
proc sort data=temp;
by loanno n;
run;
data want;
 set temp;
 by loanno n;
 if first.n and last.n then flag='unequal';
  else flag='equal   ';
run;