/in/foo.c: In function 'main':
/in/foo.c:7:6: warning: 'gets' is deprecated [-Wdeprecated-declarations]
      gets(a);
      ^~~~
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:11:15: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  {if(a[i]>='a'&&a[i]<='z'-k||a[i]>='A'&&a[i]<='Z'-k)
      ~~~~~~~~~^~~~~~~~~~~~~
/in/foo.c:14:21: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(a[i]>=('z'-k+1)&&a[i]<='z'||a[i]>=('Z'-k+1)&&a[i]<='Z')
      ~~~~~~~~~~~~~~~^~~~~~~~~~~
/tmp/ccglPQ1K.o: In function `main':
foo.c:(.text.startup+0x11): warning: the `gets' function is dangerous and should not be used.