Int2Str

[sunaj]

Hi,

What wouldn't I give for a Int2Str fortran function!

In thread214-1521223 mikrom shows how to make a function which returns a variable length character. The problem is that I do not know the length of the return string until a have 'written' it into a string and trimmed it - and I can do that until after the declarations.. any solutions?

    function int2Str(i)
        character(len=????) :: int2Str
        integer, intent(in) :: i
        
        character(20) :: c
        write (c,'(i20)') i
        int2Str = trim(adjustl(c))
    end function int2Str

Sunaj
'The gap between theory and practice is not as wide in theory as it is in practice'

 

[mikrom]

I don't know how to make the function result of variable length. But why not to use fixed length? You can then trim the resulting string.

[COLOR=#a020f0]program[/color] integer_to_string
  [COLOR=#2e8b57][b]integer[/b][/color] :: int_var
  [COLOR=#2e8b57][b]character[/b][/color]([COLOR=#ff00ff]20[/color]) :: string_var

  int_var[COLOR=#804040][b]=[/b][/color][COLOR=#ff00ff]12345[/color]
  [COLOR=#0000ff]! convert integer to string using[/color]
  string_var [COLOR=#804040][b]=[/b][/color] int2str(int_var)
  [COLOR=#804040][b]write[/b][/color]([COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]'(a,a)'[/color])  [COLOR=#ff00ff]'result of int2str     ='[/color], string_var  
  [COLOR=#804040][b]write[/b][/color]([COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]'(a,i2)'[/color]) [COLOR=#ff00ff]'result length         ='[/color], [COLOR=#008080]len[/color](string_var)  
  [COLOR=#804040][b]write[/b][/color]([COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]'(a,i2)'[/color]) [COLOR=#ff00ff]'trimmed result length ='[/color], [COLOR=#008080]len_trim[/color](string_var)  
  [COLOR=#804040][b]write[/b][/color]([COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]'(a,i2)'[/color]) [COLOR=#ff00ff]'trimmed result length ='[/color], [COLOR=#008080]len[/color]([COLOR=#008080]trim[/color](string_var))  

[COLOR=#a020f0]contains[/color]
  [COLOR=#2e8b57][b]character[/b][/color]([COLOR=#ff00ff]20[/color]) [COLOR=#a020f0]function[/color] int2str(num) 
     [COLOR=#2e8b57][b]integer[/b][/color], [COLOR=#2e8b57][b]intent[/b][/color]([COLOR=#2e8b57][b]in[/b][/color]):: num
     [COLOR=#2e8b57][b]character[/b][/color]([COLOR=#ff00ff]20[/color]) :: str
     [COLOR=#0000ff]! convert integer to string using formatted write[/color]
     [COLOR=#804040][b]write[/b][/color](str, [COLOR=#ff00ff]'(i20)'[/color]) num
     int2str [COLOR=#804040][b]=[/b][/color] [COLOR=#008080]adjustl[/color](str)
  [COLOR=#a020f0]end function[/color] int2str
[COLOR=#a020f0]end program[/color]

$ g95 int2str.f95 -o int2str

$ int2str
result of int2str     =12345               
result length         =20
trimmed result length = 5
trimmed result length = 5

 

[sunaj]

Ok, that'll have to do. Thx.


Sunaj
'The gap between theory and practice is not as wide in theory as it is in practice'

 

[xwb]

The maximum length is the number of digits in a number of that size. For instance, in a integer*2, the maximum is 32768 which is 5. Add 1 for negative numbers so it is 6.

For a 32 bit number integer*4, it is 2147483647 which is 10 digits. Add 1 for negative numbers so it is 11.

If, like me, you cannot remember these figures, pop up the calculator in scientific mode. Switch to hex, and type 7FFF for integer*2, 7FFFFFFF for integer*4 and then switch to decimal. If your calculator can take it, 7FFFFFFFFFFFFFFF is the max for integer*8.