small changes to old Fortran code

I need to change output format as well input data format ( both ASCII). The FORTRAN code is old and not documented , but the changes are simple at present the output is XX+ 2.3 2.6 0.3 11.7 27.0 35.7 44.4 54.0 59.0 51.0 and I need it to be XX 20100408 44.4 20100409 35.7 20100412 27.0 20100413 11.7 20100414 0.3 20100415 2.6 20100416 2.3 fist column is the date from data , this needs to added to the output the second column is the output in reversed order from above data input at the present is in the following format 20100408, 4233 20100409, 4275 20100412, 4213 20100413, 4365 20100414, 4404 20100415, 4190 20100416, 4243 need to add ability to read up to 7 column of data file and select any of the column for analysis , only one column of data be used for analysis . for example 20101006,48.44,49.32,48.23,49.08,3453900 20101007,49.47,49.6,48.1,48.51,5149400 20101008,48.7,49.19,48.66,49.08,3167600 load data with 6 columns like above and use only the fifth column for analysis