File I/O with lex/yacc

[George Bogatko]

In article <1990Aug29.172830.14348 at cunixf.cc.columbia.edu>, gld at cunixd.cc.columbia.edu (Gary L Dare) writes:
> 
> Is there any way to get around the use of standard input/output in a
> lex file???  The C file generated by lex (from the lexical analyzer

There are two ways.
1.  Use freopen(...stdin) freopen(...stdout).

    freopen("your_in_file", "r", stdin);
    freopen("your_out_file", "w", stderr;

2. use a close/open combination, ala:

	close(0);
	open("your_in_file", ...);
	close(1);
	open("your_out_file", ...);
	blah, blah, blah.

   the second way can be useful if you want to use lex to parse the input from
   a tty line different than your terminal line.

Method 1 is far less messy than method 2.

GB