/***************************************************************

   yr4digit

   Converts 2-digit years to 4 digit years, if necessary.
   Assumes the true year is after 1970; hence good to 2070.
   There is no error checking.

                        Sun  98/06/07

    2014/05/26: changed to modify only 1- and 2-digit years.

***************************************************************/

int yr4digit(int yr)
{
    if (yr < 70)
    {
        yr += 2000;
    }
    else if (yr >= 70 && yr < 100)
    {
        yr += 1900;
    }
    return(yr);
}