February  5 2008   2:50:17.728 PM
 
EXPONENT_FORMAT_OVERFLOW:
  FORTRAN90 version.
 
TEST01
  Real numbers can have exponents greater than 99.
 
  It is unsettling to discover that there is a
  common FLAW in certain output formats, which means
  that the printing of real numbers with exponents
  of magnitude more than 99 is handled poorly.
 
  The "E" marker, used to indicate scientific notation,
  is simply suppressed, as though to make room for
  the leading digit of the exponent.
 
  But this inconsistency can be deadly.  In particular,
  if you write out such data, it CANNOT be read back in
  properly!  (THAT example is easy to write, but I will
  do that later.)
 
  Define some big numbers:
 
  X1 = huge ( X1 )
  X2 = 0.99D+00 * X1
  X3 = X1 / 100.0D+00
  X4 = 1.0D+101.
 
  Define some small numbers:
 
  X5 = tiny ( X5 )
  X6 = 1.01D+00 * X5
  X7 = X5 * 100.0D+00
  X8 = 1.0D-101.
 
  Define some comparison numbers:
 
  X9  = 1.0D+98
  X10 = 1.0D-98
  X11 = 123456789.0
  X12 = 0.123456789
 
  Print with a WRITE(*,*) format:
  This seems to work OK:
 
   X1 =   1.79769313486231571E+308
   X2 =   1.77971620351369253E+308
   X3 =   1.79769313486231576E+307
   X4 =   9.99999999999999977E+100
   X5 =   2.22507385850720138E-308
   X6 =   2.24732459709227342E-308
   X7 =   2.22507385850720138E-306
   X8 =   1.00000000000000005E-101
   X9 =   9.99999999999999998E+097
   X10 =   9.99999999999999939E-099
   X11 =    123456789.00000000     
   X12 =   0.12345678900000000     
 
  Print with a WRITE(*,'(G24.10)') format:
  Notice the disaster:
 
  X1 =         0.1797693135+309
  X2 =         0.1779716204+309
  X3 =         0.1797693135+308
  X4 =         0.1000000000+102
  X5 =         0.2225073859-307
  X6 =         0.2247324597-307
  X7 =         0.2225073859-305
  X8 =         0.1000000000-100
  X9 =         0.1000000000E+99
  X10 =         0.1000000000E-97
  X11 =          123456789.0    
  X12 =         0.1234567890    
 
  Print with a WRITE(*,'(D24.10)') format:
  Same disaster:
 
  X1 =         0.1797693135+309
  X2 =         0.1779716204+309
  X3 =         0.1797693135+308
  X4 =         0.1000000000+102
  X5 =         0.2225073859-307
  X6 =         0.2247324597-307
  X7 =         0.2225073859-305
  X8 =         0.1000000000-100
  X9 =         0.1000000000D+99
  X10 =         0.1000000000D-97
  X11 =         0.1234567890D+09
  X12 =         0.1234567890D+00
 
  Print with a WRITE(*,'(E24.10)') format:
  Same disaster:
 
  X1 =         0.1797693135+309
  X2 =         0.1779716204+309
  X3 =         0.1797693135+308
  X4 =         0.1000000000+102
  X5 =         0.2225073859-307
  X6 =         0.2247324597-307
  X7 =         0.2225073859-305
  X8 =         0.1000000000-100
  X9 =         0.1000000000E+99
  X10 =         0.1000000000E-97
  X11 =         0.1234567890E+09
  X12 =         0.1234567890E+00
 
EXPONENT_FORMAT_OVERFLOW:
  Normal end of execution.
 
February  5 2008   2:50:17.731 PM