使用Fortran 90在输入文件中正确读取注释行 [英] Reading comment lines correctly in an input file using Fortran 90

问题描述

据我的理解，Fortran在从文件读取数据时，将跳过以星号（*）开头的行，假设它们是注释。好吧，我似乎有一个问题，实现这个行为，我创建了一个非常简单的程序。这是我简单的Fortran程序：

It is my understanding that Fortran, when reading data from file, will skip lines starting with and asterisk (*) assuming that they are a comment. Well, I seem to be having a problem with achieving this behavior with a very simple program I created. This is my simple Fortran program:

  1       program test
  2 
  3       integer dat1
  4 
  5       open(unit=1,file="file.inp")
  6 
  7       read(1,*) dat1
  8 
  9 
 10       end program test

这是file.inp：

This is "file.inp":

  1 *Hello
  2 1

$ b b

我用

I built my simple program with

gfortran -g -o test test.f90

运行时出现错误：

At line 7 of file test.f90 (unit = 1, file = 'file.inp')
Fortran runtime error: Bad integer for item 1 in list input

当我运行删除注释行的输入文件，即：

When I run the input file with the comment line deleted, i.e.:

1 1

代码运行正常。所以似乎是一个问题，Fortran正确解释的注释行。

The code runs fine. So it seems to be a problem with Fortran correctly interpreting that comment line. It must be something exceedingly simple I'm missing here, but I can't turn up anything on google.

推荐答案

Fortran doesn不会自动跳过输入文件中的注释行。你可以很容易地做到这一点，首先读取行到一个字符串，检查第一个字符的注释符号或搜索字符串的那个符号，然后如果该行不是一个注释，做一个内部读取字符串

Fortran doesn't automatically skip comments lines in input files. You can do this easily enough by first reading the line into a string, checking the first character for your comment symbol or search the string for that symbol, then if the line is not a comment, doing an "internal read" of the string to obtain the numeric value.

类似于：

use, intrinsic :: iso_fortran_env

character (len=200) :: line
integer :: dat1, RetCode

read_loop: do
   read (1, '(A)', isostat=RetCode)  line
    if ( RetCode == iostat_end)  exit ReadLoop
    if ( RetCode /= 0 ) then
      ... read error
      exit ReadLoop
    end if
    if ( index (line, "*") /= 0 )  cycle read_loop
    read (line, *) dat1
end do read_loop

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