diff options
Diffstat (limited to 'revdonewrong.c')
-rw-r--r-- | revdonewrong.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/revdonewrong.c b/revdonewrong.c new file mode 100644 index 0000000..d6bb631 --- /dev/null +++ b/revdonewrong.c @@ -0,0 +1,42 @@ +#include <u.h> +#include <libc.h> + +void +swap(char *a, char *b) +{ + char tmp; + + tmp = *a; + *a = *b; + *b = tmp; +} + +void +rev(char *s, ulong len) +{ + char *e; + + e = s+len; + while(s != e) + swap(s++, --e); +} + +void +usage(void) +{ + fprint(2, "usage: %s text\n", argv0); + exits("usage"); +} + +void +main(int argc, char *argv[]) +{ + ARGBEGIN{ + default: usage(); + }ARGEND; + if(argc != 1) + usage(); + rev(argv[0], strlen(argv[0])); + print("%s\n", argv[0]); + exits(nil); +} |