data: abc type string,
abc_output type string,
a type i,
b type i,
c type i.
abc = A018-DATAB.
"now abc = yyyymmdd
'so if we want to format it to dd.mm.yyyy
a = abc+6(2). "get two places start with 6 character
b = abc+4(2). "get two places start with 4 character
c = abc(4). "get start four palces of abc
concatenate a b c into abc_output separate by '.'.