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 '.'.