It is obvious that this same technique was used subconsciously by humans long before computers to handle the naturally abbreviated dates. Source date lengths should be changed from 5 to 6. Source date names are chosen here only to illustrate date conversion logic. In real program more mnemonic names should be used for the source dates. Pivot Year Assumed by the Organizational Standard.
Source Dates to Be Compared.
Append Appropriate Century to the Source Dates. The most reliable way is to keep the Pivot-Year as a separate and unique COPY member to be used by all date handling programs. This approach permits to avoid any possible errors related to Pivot-Year advancement, since there is only one place where the year is changed. Process of recompiling all programs containing the Pivot-Year COPY member is quite formal and, if performed carefully, doesn't require any debugging. Continue PARM field of the JCL EXEC operator to the next line.