e指数

风平老涡

根据最后得到的实数Kind。

[Fortran] 纯文本查看 复制代码

program test_precision
  use, intrinsic :: iso_fortran_env
  implicit none
  integer, parameter :: sp = REAL32
  integer, parameter :: dp = REAL64
  integer, parameter :: qp = REAL128
  real(kind = sp) :: x1 = 0.0
  real(kind = dp) :: x2 = 0.0
  real(kind = qp) :: x3 = 0.0

  write(*,'(A,I4,A,G0,A,I6)') "Max number in ", sp*8, " bits = ", huge(x1), "   Max power to e= ", floor(log(huge(x1)))
  write(*,'(A,I4,A,G0,A,I6)') "Max number in ", dp*8, " bits = ", huge(x2), "   Max power to e= ", floor(log(huge(x2)))
  write(*,'(A,I4,A,G0,A,I6)') "Max number in ", qp*8, " bits = ", huge(x3), "   Max power to e= ", floor(log(huge(x3)))
end program test_precision

结果：
Max number in   32 bits = 0.340282347E+39   Max power to e=     88
Max number in   64 bits = 0.17976931348623157E+309   Max power to e=    709
Max number in  128 bits = 0.118973149535723176508575932662800702E+4933   Max power to e=  11356