4.3BSD - /usr/src/usr.bin/rev.c

   1: static char *sccsid = "@(#)rev.c	4.1 (Berkeley) 10/1/80";
   2: #include <stdio.h>
   3: 
   4: /* reverse lines of a file */
   5: 
   6: #define N 256
   7: char line[N];
   8: FILE *input;
   9: 
  10: main(argc,argv)
  11: char **argv;
  12: {
  13:     register i,c;
  14:     input = stdin;
  15:     do {
  16:         if(argc>1) {
  17:             if((input=fopen(argv[1],"r"))==NULL) {
  18:                 fprintf(stderr,"rev: cannot open %s\n",
  19:                     argv[1]);
  20:                 exit(1);
  21:             }
  22:         }
  23:         for(;;){
  24:             for(i=0;i<N;i++) {
  25:                 line[i] = c = getc(input);
  26:                 switch(c) {
  27:                 case EOF:
  28:                     goto eof;
  29:                 default:
  30:                     continue;
  31:                 case '\n':
  32:                     break;
  33:                 }
  34:                 break;
  35:             }
  36:             while(--i>=0)
  37:                 putc(line[i],stdout);
  38:             putc('\n',stdout);
  39:         }
  40: eof:
  41:         fclose(input);
  42:         argc--;
  43:         argv++;
  44:     } while(argc>1);
  45: }

Defined functions

Defined variables

Defined macros