/in/foo.c: In function 'main':
/in/foo.c:7:5: warning: 'gets' is deprecated [-Wdeprecated-declarations]
     gets(s);
     ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:12:15: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
 { if(s[i]>='A'&&s[i]<=('Z'-k)||s[i]>='a'&&s[i]<=('z'-k))
      ~~~~~~~~~^~~~~~~~~~~~~~~
/in/foo.c:21:2: warning: array subscript is above array bounds [-Warray-bounds]
 s[i+1]='\0';
 ~^~~~~
/tmp/cc0qP0tQ.o: In function `main':
foo.c:(.text.startup+0x11): warning: the `gets' function is dangerous and should not be used.