在C＃中实现此Fortran代码段的最佳方法是什么

Question

I have a Fortran routine which reads data from a file like this:

10   READ(X,*,ERR=8000,END=9000) ... Read header line of data sequence
C    Some processing of header line data...
     READ(X,*,ERR=8000) ... Read secondary line of data sequence
C    Some processing of secondary line data...
20   READ(X,*,ERR=8000) ... Read data line
     IF data contains 'X' GOTO 10
C    Do some calculations with the data ...
     IF (X.LT.Y)
         GOTO 10
C    Do some more calculations ...
100  CONTINUE
8000 'Output some error to the log'
9000 'Some final stuff'
     RETURN

The original code is a lot longer than this, but this is the gist. I am thinking that C# code like below should do the same thing (coding from memory, so might be some errors...), but for some reason this seems enormously complicated to achieve the same result. Is there a simple way of replicating the flow of the Fortran routine? Is it just a case where using gotos provides shorter code than using code blocks?

private void MyFunction(Stream MyData)
{
    string s = string.Empty;
    bool flag;
    StreamReader sr = new StreamReader(MyData);
    try
    {
        while (!sr.EndOFStream)
        {
            s = sr.ReadLine(); ... Read header line of data sequence
            //Some processing of header line data ...
            s = sr.Readline(); ... Read secondary line of data sequence
            //Some processing of secondary line data ...
            flag = false;
            while (!(s = sr.ReadLine()).Contains("X"))
            {
                //Do some calculations with the data ...
                if (X < Y)
                {
                    flag = true;
                    break;
                }
                //Do some more calculations ...
            }
            if (flag) continue;
        }
        //Some final stuff ...
        return;
    }
    catch
    {
         //Output error to log...
    }
}

Answer 1

Certainly the goto statements can be avoided.

It seems to me though, your C# sample is not doing the same thing as the Fortran snippet (at least I think so). I don't know C# but here is a Fortran version without gotos. It should be equivalent to the other version with one exception: I did not include the I/O error checks.

 readloop : do while(.true.)
    read(X,*,iostat=stat) ! ... Read header line of data sequence
    if (stat /= 0) exit
    ! Some processing of header line data...
    read(X,*)             ! ... Read secondary line of data sequence
    ! Some processing of secondary line data...
    read(X,*)             ! ... Read data line
    if (data contains 'X') cycle readloop
    ! Do some calculations with the data ...
    if (X >= Y) exit readloop
 end do
 ! Some final stuff

This should translate to C#-ish code as (I deduce the syntax from your code example):

 while (!sr.EndOfStream) {
   s = sr.ReadLine();
   // process
   s = sr.ReadLine();
   // process
   s = sr.ReadLine();
   if (s.Contains("X")) continue;
   // calculations
   if (X >= Y) break; 
 }
 // final processing

and it should be simple to include an error check here, using the try...catch construct.

Answer 2

When reading the third line, you may read a line multiple times.

I tend to avoid assigning a variable in a test. That makes the code hard to read.