midterm.cc

      //  $Id$
      
      /*  Satisfies the requirements for Question 4 on the Spring 2002
       *  midterm exam.
       *
       *    $Log$
       */
      #include <stdio.h>
      #include <getopt.h>
      
      //  Globals
      static const char *optstring = "ao:?";
      static const option longopts[] =
      {
        { "append",   0,  0,  'a' },
        { "outfile",  1,  0,  'o' },
        { "help",     0,  0,  '?' },
        {0, 0, 0, 0},
      };
      
      //  main()
      //  ------------------------------------------------------------------
      /*
       *    Process command line options, read input files, and write output
       *    messages giving line counts for input files.
       */
      int
      main(int argc, char *argv[], char *envp[])
      {
        int         longindex;
        //  Default option value
        bool        append  = false;
        const char *outfile = "midterm.out";
      
        //  Process options
        int optchar = -1;
        while ( -1 != (optchar = getopt_long(argc, argv, optstring,
                longopts, &longindex ) ) )
        {
          switch ( optchar )
          {
          case 'a':
            append = true;
            break;
          case 'o':
            outfile = optarg;
            break;
          default:
            fprintf( stderr,  "Usage: midterm [options] file...n"
                              "  Options:n"
                              "   -a | --append   Do not overwrite outputn"
                              "   -o | --outfile  Name of output filen"
                              "                   Default is midterm.outn"
                              "   -? | --help     Display this messagen" );
            exit( 1 );
          }
        }
      
        //  Prepare the output file for writing
        FILE  *msgfile = fopen( outfile, append ? "a" : "w" );
        if ( 0 == msgfile )
        {
          perror( outfile );
          exit( 1 );
        }
      
        //  Process input files
        while ( optind < argc )
        {
          FILE *in = fopen( argv[ optind ], "r" );
          if ( 0 == in )
          {
            // Print error message and continue for unreadable files.
            perror( argv[ optind++ ] );
            continue;
          }
      
          //  Count the lines in the file.
          int   numLines = 0;
          char inBuf[ 8192 ];
          for ( ;; )
          {
            fgets( inBuf, sizeof inBuf, in );
            if ( feof( in ) )
              break;
            numLines++;
          }
          fprintf( msgfile, "%s: %d linesn", argv[optind++], numLines );
        }
      }