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C Library Functions  - dble (3)

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NAME

dble(3f) - [M_overload::TYPE] allow dble(3f), real(3f), int(3f) to take character arguments (LICENSE:PD)

CONTENTS

Synopsis
Description
Options
Returns
Examples
Author
License

SYNOPSIS

dble(3f), real(3f), and int(3f) extension:

      pure elemental doubleprecision function dble(value)
      pure elemental real  function real(value)
      pure elemental int function int(value)

DESCRIPTION

All the intrinsics dble(3f), real(3f), and int(3f) to take a character string as an argument, assuming it represents a numeric value; or a logical value or expression.

o	[char46]true. is 0
o	[char46]false. is 1

OPTIONS

value
	string or logical expression or value to convert to a numeric value If an error occurs zero is returned.

RETURNS

A numeric value

EXAMPLES

Sample usage:

   program demo_dble

   use, intrinsic :: iso_fortran_env, only : &
           & integer_kinds, int8, int16, int32, int64
   use, intrinsic :: iso_fortran_env, only : &
           & real32, real64, real128

   use M_overload, only : int, real, dble
   use M_overload, only : merge
   implicit none
   character(len=*), parameter :: gen=’(*("[",g0,"]":,","))’
      ! basics
      ! note returns int64
      write(*,gen) int(’1234’)*2
      write(*,gen) real(’1234.56789’)*2
      write(*,gen) dble(’1234.5678901234567’)*2
      ! tests
      if(int(’1234’) .eq. 1234 ) &
              & write(*,*)’int("STRING") works ’
      if(abs(real(’1234.56789’) - 1234.56789) .lt. 2*epsilon(0.0)) &
              & write(*,*)’real("STRING") works ’
      if(abs(dble(’1234.5678901234567’) - 1234.5678901234567d0) .lt. &
      & epsilon(0.0d0)) &
              & write(*,*)’dble("STRING") works ’
      ! logical arguments work as well
      ! so let us settle this once and for all
      write(*,*)’.true. is’,int(.true.)
      write(*,*)’.false. is’,int(.false.)
      write(*,*)’LOGICAL ARRAY   ’, dble([.false., .true., .false., .true.])
      write(*,*) merge(’int works for .FALSE.’,’int fails for .FALSE.’, &
              & int(.FALSE.).ne.0)
      write(*,*) merge(’int works for .TRUE.’,’int fails for .TRUE.’, &
              & int(.TRUE.).eq.0)
      ! and also note the argument can be metamorphic
      ! call a function with a metamorphic argument so values can be
      ! any values that represent a numeric value ...
      write(*,*)’METAMORPHIC     ’, promote(1,1.0,1.0d0)
      write(*,*)’METAMORPHIC     ’, promote(’3’,(2.0,0.0),.true.)
      write(*,*)’METAMORPHIC     ’, promote(’3’,’3’,’3’)
      write(*,*)’METAMORPHIC     ’, promote(.true.,.false.,.true.)
      write(*,*)’METAMORPHIC     ’, promote((3.0,4.0),0.0,0)

   contains
   function promote(value1,value2,value3)
      class(*),intent(in) :: value1
      class(*),intent(in) :: value2
      class(*),intent(in) :: value3
      doubleprecision,allocatable :: promote
      promote=sum([dble(value1),dble(value2),dble(value3)])
   end function promote

   end program demo_dble

Results:

    > [2468]
    > [2469.13574]
    > [2469.1357802469133]
    >  int("STRING") works
    >  real("STRING") works
    >  dble("STRING") works
    >  .true. is                    0
    >  .false. is                    1
    >  LOGICAL ARRAY      1.0000 0.0000  1.0000  0.0000
    >  int works for .FALSE.
    >  int works for .TRUE.
    >  METAMORPHIC        3.0000000000000000
    >  METAMORPHIC        3.0000000000000000
    >  METAMORPHIC        9.0000000000000000
    >  METAMORPHIC        1.0000000000000000
    >  METAMORPHIC        0.0000000000000000

AUTHOR

John S. Urban

LICENSE

Public Domain

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Nemo Release 3.1

dble (3)

February 23, 2025

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