Please Help In This Formula

HELLO FRIEND,

I have accounting app and i have some problem in crystal report formula to get statement of account

for example bank statement .


Dr Cr Bal

0 100 100

0 150 350

50 0 300

20 0 280

0 140 420

PLEASE IF U KNOW ANY FORMULA TO SOLVE THIS PROBLE SEN IT

THANKStry this formula in detail section

whileprintingrecords;
numbervar a;
if dr then
a=a+dr
else
a=a-cr


if u need to reset this formula to zero , make another formula and use it in group section

whileprintingrecords;
numbervar a;
a:=0;