Internal write and read in Fortran

write can target a string, and read can parse one back.

program internal_write
    implicit none
    character(len=32) :: line
    real :: mean = 68.14
    integer :: day = 3

    ! An internal write formats into a string instead of the screen.
    write (line, '(a, i0, a, f6.2)') "day ", day, " mean ", mean
    print *, "built: [", trim(line), "]"

    ! An internal read parses text back into variables.
    read (line(5:5), '(i1)') day
    print *, "parsed the day back: ", day
end program internal_write

How it works

1. write (line, fmt) ... formats into line instead of the screen.
2. The built string prints trimmed, brackets showing its edges.
3. read (line(5:5), '(i1)') parses the day digit straight out of the text.

Keywords and builtins used here

• character
• end
• implicit
• integer
• len
• none
• print
• program
• read
• real
• trim
• write

The run, in numbers

Lines

14

Characters to type

413

Tokens

69

Three-star pace

60 tpm

At the three-star pace of 60 tokens a minute, this run takes about 69 seconds.

Type this snippet

Step 3 of 3 in Strings & formats, step 18 of 27 in Language basics.

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