BSD 4 release

[unix-history] / usr / src / cmd / rev.c

static char *sccsid = "@(#)rev.c        4.1 (Berkeley) 10/1/80";
#include <stdio.h>

/* reverse lines of a file */

#define N 256
char line[N];
FILE *input;

main(argc,argv)
char **argv;
{
       register i,c;
       input = stdin;
       do {
               if(argc>1) {
                       if((input=fopen(argv[1],"r"))==NULL) {
                               fprintf(stderr,"rev: cannot open %s\n",
                                       argv[1]);
                               exit(1);
                       }
               }
               for(;;){
                       for(i=0;i<N;i++) {
                               line[i] = c = getc(input);
                               switch(c) {
                               case EOF:
                                       goto eof;
                               default:
                                       continue;
                               case '\n':
                                       break;
                               }
                               break;
                       }
                       while(--i>=0)
                               putc(line[i],stdout);
                       putc('\n',stdout);
               }
eof:
               fclose(input);
               argc--;
               argv++;
       } while(argc>1);
}